Review of Mine Water Reports in the Hotazel, Kathu and Postmasburg Areas, Northern Cape

Review of mine water reports in the Hotazel, Kathu and Postmasburg areas, Northern Cape

Dr. Kevin Pietersen with contributions from Zaheed Gaffoor Reviewer: Dr. Hans Beekman

Client: Agri Northern Cape November 2017 Final Report

Review of mine water reports in the Hotazel, Kathu and Postmasburg areas, Northern Cape

EXECUTIVE SUMMARY

Since the 1930s there have been numerous investigations to better understand the hydrogeology of the Hotazel, Kathu (Sishen) and Postmasburg areas in the Northern Cape. There have been concerns about the dewatering operations of the Sishen Iron Mine but there has been limited consideration in the studies of the cumulative dewatering impact of all water users: agriculture, mining, (proposed) solar power generation facilities and water supply, in the region – so called cumulative management. This has led to concerns about the sustainability of groundwater abstractions in the region. This study was a desk-top review of groundwater literature with the aim to understand the issues in more detail.

The most significant impact of the mines in the region has been the dewatering of the aquifers. The sources of water for dewatering are the banded iron formations (BIF) and dolomites of the Ghaap Group. To predict changes in hydrogeological conditions resulting from mine dewatering, the mines have constructed groundwater models at a local scale with limited consideration of a broader perspective, i.e. a regional and holistic approach. A regional and holistic approach allows for the assessment and evaluation of the combined effect of abstractions of all stakeholders on the groundwater resources and ultimately allows for appropriate groundwater management interventions. Note that the groundwater modelling studies in the area were commissioned by the mines and are not easily available in the public domain. The extent of the dewatering zones of the Sishen Iron Ore Mine has been investigated extensively, whilst for the other mines in the region there were no such detailed investigations accessible.

Groundwater discharge processes include evaporation and transpiration of groundwater, and groundwater ﬂow to the surface (seepage), including discharge to wetlands and rivers and subsurface drainage. In semi-arid areas with relatively low rainfall, quantification of groundwater recharge is complex because its rate is only a very small fraction of the water balance (usually less than 5% of the average annual rainfall). Recharge events in such environments are predominantly episodic or intermittent. This means that rainfall is percolating to the water table only during extreme (surplus) rainfall events. The dewatering of the aquifer systems means that flowing springs disappear and

i baseflow is absent, giving rise to dry river beds (e.g. the Gamagara River). There seems to be no major visible discharge areas in the aquifer systems except for possible discharge zones in the Skeifontein Spruit. The natural groundwater drainage is from the eastern catchment boundary (recharge area) in the east (Kuruman Hills) towards the outflow area at Dibeng. Recharge can be local and indirect and is also induced as a result of the dewatering activities. The Gamagara River is a gaining river outside the zone of dewatering. Inside the dewatered zone (Moria to Demaneng and Demaneng to Mokaning), the Gamagara River is a losing stream (recharging the aquifer). The aquifer is over-exploited (abstraction from the aquifer exceeds sustainable rates). Discharge areas are difficult to identify as the compartments are dewatered so the open pits are sinks to groundwater flow in the region.

The absence of a holistic and integrated regional study makes it difficult to evaluate the implications of large-scale groundwater abstraction on competing users. There are concerns from stakeholders that water use licenses are issued without due regard of the cumulative impact of these abstractions on the groundwater resources. The catchments are water stressed (see reserve determinations). The water (consumption) footprint is dominated by demand from the mining sector, followed by Local Municipalities, agricultural sector and power generation. The challenge remains not only the provision of adequate volumes of water for local economic development but also taking into account spatial and temporal requirements. Only few studies have been conducted to understand the cumulative implications of mine dewatering and large-scale abstraction on competing groundwater users.

The decision-making framework developed by Seyler et al. [1] together with the groundwater governance frameworks developed by Pietersen et al. [2,3] was used as a basis for analysis of the sustainability of the resource. The analysis revealed the following:

The current use of groundwater is unsustainable. In the catchments there are competing demands for groundwater consumption, i.e. water supply for domestic and industrial use and for agricultural purposes. Inspections and investigations by Department of Water and Sanitation (DWS) indicated that a number of mines in the region are operating without the needed water use authorizations. The management of the groundwater resources must take into consideration not only technical issues but also social and environmental aspects. The framework categories identified in the table below were adapted to the local situation to analyse the sustainability provisions for groundwater management in the region. In undertaking the analysis, any areas where parts of the sustainability provisions are not addressed represent a ‘gap’. The analysis reflected in the table is based on

ii numerous sources of information being provided and which were compiled, reviewed, and mined using a framework analysis. Each of the identified gaps was categorised and colour-coded to reflect the magnitude of the gap: (a) green (3) – criteria are met; (b) amber (2) – criteria partially met; (c) red (1) – significant gap or absent.

Table: Framework for analysis of sustainability provisions.

Capacity Criterion Context Gap Technical Basic hydrogeological maps For identification of groundwater 3 resources Groundwater body/aquifer delineation With classification of typology 3 Availability of aquifer numerical At least preliminary for strategic critical 3 ‘management models’ aquifers Change in natural discharge Detection of change in water table 2 towards discharge point Assessment of discharge 2 Flow in discharge-receiving 2 environment Chemical composition of discharge- 1 receiving environment Change in pre-abstraction recharge Detection of change in water table 2 towards recharge zone Direct detection of change in water 2 table in recharge zone Indirect detection of change in water 1 table in recharge zone Assessment of surface water flows in 2 recharge zone Chemical tracer for recharge source 1 Increased recharge 2 Change in storage Detection of change in water table 2 Response time/status of aquifer Age of water 1 towards new dynamic equilibrium Quantification of the relationship The shape, gradient and scales of the between increasing abstraction and curves will vary for each system 2 reducing discharge and other aquifer flows Recovery assessment If this is very long, then the flows at a reasonable water supply planning and 1 environmental timescale should be determined Legal and Water well drilling permits & For large users, with interests of small 2 institutional groundwater use rights users noted Instruments to reduce groundwater Water well closure/constraint in critical 1 abstraction areas Instruments to prevent water well In overexploited or polluted areas 1 construction Sanction for illegal water well Penalizing excessive pumping above 1 operation permit Groundwater abstraction & use ‘Resource charge’ on larger users 1 charging Land use control on potentially Prohibition or restriction since 2 polluting activities groundwater hazard Levies on generation/discharge of Providing incentives for pollution 1 potential pollutants prevention Government agency as ‘groundwater Empowered to act on cross-sectoral 2 resource guardian’ basis Community aquifer management Mobilising and formalising community 2 organisations participation Cross-Sector Coordination with agricultural, mineral Ensuring ‘real water saving’ and 2 Policy and social development pollution control Coordination Groundwater based urban/industrial To conserve and protect groundwater 2 planning resources Compensation for groundwater Related to constraints on land-use 2 protection activities

iii

Capacity Criterion Context Gap Operational Public participation in groundwater Effective in control of exploitation and 1 management pollution Existence of groundwater With measures and instruments 2 management action plan agreed

This analysis has highlighted gaps that need to be addressed to support sustainable development of groundwater resources in the region. The indicators which are not met focus on priority interventions.

An approach similar to a strategic environmental assessment is required to analyse the cumulative impact of large-scale groundwater dewatering and abstraction on groundwater users and environment. The groundwater resources and particularly the dolomite aquifers are at risk of being dewatered unless regulations are enforced. Based on the evaluation of numerous reports and the gap analysis, I would recommend to:

 Establish a groundwater monitoring network that takes into account monitoring of recharge and discharge areas;  Establish a standardised regional digital relational database that combines data from all water users. The design should accommodate for all monitoring points, all categories of data and different data collection scheduling (frequency), and inclusion of historical data. Use of a common database will facilitate comparison among different sites;  Access to the common database for all water users; and  Develop a regional numerical model(s) to address the gaps identified in the framework analysis.

In conclusion, a technical-institutional model is required that facilitates decision-making and trust among all stakeholders.

TABLE OF CONTENTS

Executive Summary ...... i Table of Contents ...... v List of figures ...... v List of tables ...... vi List of appendices ...... vii List of acronyms ...... vii 1. Introduction ...... 1 2. Site description and background ...... 5 3. Approach to the Assignment ...... 8 4. Results ...... 9 4.1. Scale and impact of mine dewatering ...... 9

4.2. Discharge and recharge areas ...... 21

4.3. Groundwater use and interference ...... 29

4.4. Cumulative impacts ...... 32

5. Discussion ...... 34 6. Conclusion ...... 37 7. Acknowledgements ...... 39 8. References ...... 39 Appendix 1: Review of mine and related water reports ...... 42

LIST OF FIGURES

Figure 1: Regional geological map of the Maremane Dome region in the Northern Cape Province indicating the location of the Sishen, Khumani, Beeshoek and Sishen South iron ore deposits (modified after Van Schalkwyk and Beukes, 1986 as cited by Smith and Beukes [5])...... 2 Figure 2: (a) Regional map of the Transvaal Supergroup in Griqualand West showing the distribution of the Kalahari Manganese Field and Black Ridge thrust fault. (b) Schematic diagram indicating lateral interfingering of the Hotazel and Mooidraai formations of the KMF on the Kaapvaal Craton to the east, in the footwall of the Black Ridge thrust fault with the Beaumont Formation to the west off the craton in the hangingwall of the thrust (from Cairncross and Beukes, 2013 as cited by Beukes et al [6])...... 3

Figure 3: Location map of area under investigation showing rivers, mines, population centres and proposed renewable power generation stations...... 5 Figure 4: Water use by sector in 2015 and 2030 from the Vaal Gamagara Water Supply Scheme [14]. The 2015 water use figures for Kalahari East include agriculture water use...... 6 Figure 5: Generalized hydrogeological framework of the study area [22]...... 7 Figure 6: Current licenced abstraction and dewatering volumes (m3/a) as per water use license authorisations...... 10 Figure 7: Groundwater compartments and impacted zone 2016 (Meyer (2016) as cited by Exigo [17])...... 12 Figure 8: Dewatering volumes from Sishen Iron Mine [34]...... 14 Figure 9: Cumulative dewatering of Sishen Iron Mine [34]...... 15 Figure 10: Representation of the groundwater levels in the dewatering compartment before and after dewatering activities [12]...... 16 Figure 11: Sishen Mine Compartments and future simulated impact zones - 2032 (Itasca, 2016 as cited by Exigo [17])...... 17 Figure 12: Example hydrograph in the Sishen and Postmasburg area...... 20 Figure 13: Piezometric Map of the D41J and D73A quaternary catchments based on the 2013 groundwater level elevations [67]...... 23 Figure 14: Local map showing the land cover with comparison between a dry (2013) and a wet (1990) year [66]...... 24 Figure 15: D41J monthly rainfall 1920-2009 (WR2012) [66]...... 26 Figure 16: D73A monthly rainfall 1920-2009 (WR2012) [66]...... 27 Figure 17: Water level vs rainfall in boreholes outside the July 2010 dewatering zone [12]...... 28 Figure 18: Cumulative ground water abstraction compared to cumulative ground water [15]...... 29 Figure 19: Source development areas [68]...... 30 Figure 20: Water balance - Vaal River and Source Development (SD) sources [14]...... 30

LIST OF TABLES

Table 1: Mines that were monitored in the 2016/2017 financial year by the DWS [29]...... 11 Table 2: Groundwater compartments and zones [17]...... 12 Table 3: Groundwater levels and impacted zones [17]...... 14

Table 4: Summary of Golder detailed Reserve determination (2015) volume in Mm3/a as cited by van Dyk [8]...... 31 Table 5: Solar power plants and their water requirements...... 32 Table 6: A framework for analysis of sustainability provisions [1–3]...... 34

LIST OF APPENDICES

Appendix 1: Review of mine and related water reports ...... 42

LIST OF ACRONYMS

BIF Banded iron formations DWS Department of Water and Sanitation GMUs Groundwater Management Units KMF Kalahari Manganese Fields m³/a Cubic metres per annum

vii

1. INTRODUCTION

The Northern Cape Province has significant mineral deposits of iron ore and manganese associated with the Transvaal Supergroup1 which are preserved in the Griqualand West Basin. The Griqualand West Basin consists of a basal carbonate platform sequence, which is conformably overlain by the banded iron formation (BIF), and in turn is overlain by chemical and clastic sediments that are succeeded by Makganyene Formation diamictite and Ongeluk Formation basalt and basaltic andesite [4]. Currently, the bulk of South Africa’s iron ore production comes from four mines (Figure 1) on the Maremane Dome2 in Griqualand West, namely the Sishen and Khumani Mines along the northern margin of the dome, and the Beeshoek and Kolomela Mines in the south [5]. Limestone is also mined locally at places such as Lime Acres. The Kalahari Manganese Fields (KMF), located in the Hotazel Formation of the Postmasburg Group, is the largest single manganese depository in the world and accommodates for all of the country’s manganese mines [6]. The iron and manganese mine require dewatering as part of their mining operations. The consequences of water table depression due to mine dewatering include [7]:

(a) Decreased flows in streams and wetlands that are in hydraulic contact with the affected groundwater body; (b) Lowering of the water table in the vicinity of water supply/irrigation boreholes, leading to an increase in the pumping head (and therefore in pumping costs), if not to the complete drying up of boreholes; (c) Collapse of voids in karstic terrains as buoyant support is withdrawn; and (d) Surface water and/or groundwater pollution, if the pumped mine water is of poor quality and is discharged to the natural environment without prior treatment.

1 The late Archaean to early Proterozoic Transvaal Group is preserved within three structural basins on the Kaapvaal Craton of Southern Africa: the Transvaal and Griqualand West Basins in South Africa and the Kanye Basin in Botswana [87]. 2 Dolomite and limestone deposits of the Campbell Rand Subgroup.

Figure 2: (a) Regional map of the Transvaal Supergroup in Griqualand West showing the distribution of the Kalahari Manganese Field and Black Ridge thrust fault. (b) Schematic diagram indicating lateral interfingering of the Hotazel and Mooidraai formations of the KMF on the Kaapvaal Craton to the east, in the footwall of the Black Ridge thrust fault with the Beaumont Formation to the west off the craton in the hangingwall of the thrust (from Cairncross and Beukes, 2013 as cited by Beukes et al [6]).

Since the 1930s there have been numerous investigations to better understand the hydrogeology of the Postmasburg and Sishen areas in the Northern Cape. There have been concerns about the dewatering operations of the Sishen Iron Mine but there has been limited consideration in the studies of the cumulative dewatering impact of all water users: agriculture, mining, (proposed) solar power generation facilities and water supply, in the region – so called cumulative management. This has led to concerns about the sustainability of groundwater abstractions in the region [8,9]. This study is a desk-top review of groundwater literature with the aim to understand the issues in more detail:

 Sources of water for mine dewatering;  Recharge and discharge areas;  Existing groundwater use and interference (including cumulative impacts); and  Sustainability of the resource.

2. SITE DESCRIPTION AND BACKGROUND

The study area predominantly falls within the D4 and D7 secondary catchments of the Vaal Water Management Area (Figure 3). The ephemeral Gamagara River drains the area and flows westward to join the Kuruman River further downstream. Possibly 97% of the time the [Gamagara] River is dry, but during heavy downpours, as sometimes happens during the summer rainfall season, strong flows occur [10,11]. Smaller flows are attenuated rapidly in the dry soils while the larger flows travel further and these flows last at most for a few days before the water disappears into the [Gamagara] River bed along the length of the river [10,11]. Transmission losses in the Gamagara River increased in association with the mining dewatering activities in the dewatering zone, as well as due to the swallets [12,13].

Figure 3: Location map of area under investigation showing rivers, mines, population centres and proposed renewable power generation stations.

The Vaal Gamagara Water Supply Scheme3 from Delportshoop to beyond Hotazel is the main bulk regional water infrastructure but has exceeded its lifespan [14]. The Vaal River water is augmented with groundwater sourced from dewatering activities at Beeshoek and Sishen Iron Ore Mines. Current demands from the Vaal Gamagara Water Supply Scheme are about 20 million cubic metres per annum (m3/a) (Figure 4). There are plans in place by the Department of Sanitation (DWS) to upgrade the Vaal Gamagara Water Supply Scheme to meet the projected 2030 demand of 35 - 40 million m³/a. The local municipalities requiring water supply are: Dikgatlong, Tsantsabane, Gamagara, and Joe Morolong. The region relies on mining for economic prosperity and mining is the major water user in the region. The other users include agriculture (mainly stock watering along the scheme and agricultural and domestic use), government water supply (Lohatla Military Base, Koopmansfontein Experimental Farm and others) and also potential solar power projects [14]. Agriculture water use requirements for 2030 are estimated at 0.1 million m3/a representing less than 1% of the demand.

20 Millions

5 2015

Agriculture Kalahari East Miningand Industry Government and Parastatals Botswana

Localmunicipalities 2030 Water use and demand projectsions m3/a projectsions demand and use Water

Figure 4: Water use by sector in 2015 and 2030 from the Vaal Gamagara Water Supply Scheme [14]. The 2015 water use figures for Kalahari East include agriculture water use.

3 The Vaal Gamagara Water Supply Scheme was completed in the late sixties with the purpose to supply Vaal River water to the arid areas of the Gamagara valley near Postmasburg and north thereof [14]. This was done to enable large scale diamond mining at Lime Acres and the mining of iron ore and manganese at Beeshoek, Sishen, Mamatwan, Hotazel and Blackrock [14]. Several local authorities receive water from the scheme of which the towns of Delportshoop, Postmasburg, Kathu and Hotazel are the largest [14]. The Kalahari East scheme was completed in 1992 to supply domestic and stock water to an area of approximately 1 412 000 hectares that includes more than 250 farms [14].

Two major aquifer4 systems have been identified in the region [15] (Figure 5). The deeper secondary aquifers are present in the dolomite and BIF. These aquifers are associated with fracturing and weathering of the formations and are compartmentalised with dykes and other aquitards5, such as the Dwyka Group (tillite) and some formations of the Kalahari Group [11,16,17]. The groundwater flow is controlled by the regional dykes and faults [18]. A shallow aquifer is developed within the Kalahari sediments, mainly within the calcrete beds [11,19]. A shallow alluvial aquifer is also associated with the Gamagara River alluvial6 deposits [16,17]. The shallow aquifers can be separated from the deep aquifers by lower permeability dykes or clayey layers [16]. There is reference to a confined fractured Dwyka aquifer by SLR [20,21] that overlies older lithologies of the Ongeluk Andesite and Asbestos Hills formations.

Vv Joints and fractures in the quartzites that dominate the Volop Group (Vv) can be targeted for groundwater development. Yields up to 2l/s can be obtained. Better quality groundwater is associated with higher yielding areas. Vo Weathered zones and occasional joints and fractures in the andesitic lavas and infrequent interbeds of chert and jasper, as well as basal (Makganyene Formation) diamictite, all of the Postmasburg Group (Vo) can be recommended for development. Yields generally not exceeding 2l/s and electrical conductivities (EC) of less than 300mS/m can be anticipated. T-Qk Glacial valleys formed during Dwyka Group (C-Pd) times and filled with tillite and subsequently with Kalahari Group (T-Qk) sediments offer usable groundwater with yields of up to 2l/s and ECs averaging less 300mS/m. Va The groundwater potential of the BIF of the Ghaap Group (Va) is limited but yields of up to 2l/s can be obtained in joints and fractures associated with faults and diabase dykes. Va Dolomite of the Ghaap Group (Va) generally has good groundwater potential and yields more than 2l/s are common. Groundwater can be developed from fractures, joints and solution cavities commonly associated with faults and diabase dykes, as well as from fractured, subordinate carbonaceous shale beds. Faults and dykes can be easily targeted due to the occurrence of calcrete mounds and trees along these structures. Solid structureless dolomite, however, should be avoided when siting boreholes.

Figure 5: Generalized hydrogeological framework of the study area [22].

4 Rock or sediment in a formation, group of formations, or part of formation that is saturated and sufficiently permeable to transmit economic quantities of water [88]. 5 A low-permeability unit that can store groundwater and also transmit it slowly from one aquifer to another [88]. 6 Sediments deposited by rivers.

3. APPROACH TO THE ASSIGNMENT

The analysis in this report is based on numerous sources of information provided by the Client which were compiled, reviewed and mined using a framework analysis [50]. The decision-making framework developed by Seyler et al. [1] together with groundwater governance frameworks developed by Pietersen et al. [2,3] was used as a basis for analysis of the sustainability of the resource. The framework method is an excellent tool for supporting thematic (qualitative content) analysis because it provides a systematic model for managing and mapping the data. The conclusions of the mine reports reviewed are given as a compendium in Appendix 1.

4. RESULTS

4.1. Scale and impact of mine dewatering

Dewatering is required for safe operations of mine workings both to ensure access to the mineral reserves and to ensure safety of personnel and protection of equipment. Mine dewatering is normally achieved by lowering the water table and disposal of the pumped water. The abstraction of groundwater will eventually be matched by some combination of the following three responses [7]:

(a) Decrease in the volume of groundwater in natural storage; (b) Increase in the rate of groundwater recharge; and (c) Decrease in the rate of natural groundwater discharge.

Current dewatering and groundwater abstraction activities are dominated by Sishen Iron Ore Mine and Kolomela Iron Ore Mine as shown in Figure 6. The National Water Act lists a number of water uses, which includes section 21(a) taking water from a water source and section 21(j) removing, discharging or disposing of water found underground if it is necessary for the efficient continuation of an activity or for the safety of people [23]. The National Water Act [23] provides the legal framework for water regulation in South Africa. Water authorization is regulated through water use licenses. To achieve the reforms as guided by the principles of equity and sustainability, the National Water Act must authorise water use with conditions in order to regulate the use, flow and control of all water in the country [23,24]. The weak administration of water use licenses and enforcement of water use license conditions has resulted in water users operating illegally, with frequent transgressions and non-compliance with water use conditions [25– 27].

Millions 30

Beeshoek Direleton Mineralsand Energy FinchMine Kolomela PPCLime Acres PMG BishopMine Sedibeng IronOre mine Sishen IronOre Mine West DiamondEnd Mine

Section 21(a) Section 21(j)

Figure 6: Current licenced abstraction (section 21(a)) and dewatering volumes (section 21(j)) (m3/a) as per water use license authorisations.

Inspections and investigations indicated that a number of mines [in the region] are operating without the required water use authorizations [28]. There are 37 water users listed, consisting of 30 mines, 1 domestic supplier and 6 industries generating solar power (Figure 3). Thirteen of the water users are authorized with the remaining unauthorized or in the process of application or application being processed [28]. Table 1 lists the mines in the Northern Cape that were monitored in the 2016/2017 financial year by the DWS. Out of 111 mines that were monitored countrywide during the 2016/2017 financial year, 55 mines were found to be significantly in breach of the conditions of the water use license of which 25 mines were referred for enforcement actions [29]. The other 30 mines were requested to provide action plans to address non-compliance [29].

Table 1: Mines that were monitored in the 2016/2017 financial year by the DWS [29].

Mine Name Finding/Motivation Kalagadi Manganese Mine Good but at risk 50-74% PMG Not acceptable 0-24% Hotazel Manganese Mine: Hotazel site Not acceptable 0-24% Hotazel Manganese Mine: Wessels Mine Not acceptable 0-24% Hotazel Manganese Mine: Middleplaats Not acceptable 0-24% Hotazel Manganese Mine: Mamatwan mine Not acceptable 0-24% Schmidtsdrift Mine Not acceptable 25-49% Assmang: Black Rock Not acceptable 0-24% Huatian Manganese Good but at risk 50-74% Rooipoort Mine Not acceptable 25-49% Mr M Mdlulane Acceptable 75-100% MN Mbonose Acceptable 75-100% Sishen Iron Ore Not acceptable 25-49% Scarlet Sun Mine Not acceptable 25-49% De Beer Micro Diamonds Good but at risk 50-74% Mr OA Witkoei Acceptable 75-100% HE Louw Acceptable 75-100% Mrs FE Mali Acceptable 75-100% BM Marman Acceptable 75-100% Crown Resources Not acceptable 25-49%

The dewatering of the mines has a negative impact on groundwater users and the Gamagara River [12]. There has been loss of aquifer pressure [12,15,30,31] and consequential leakage from aquifers and river systems [12,15,30–32].

The groundwater systems have been compartmentalised by numerous subvertical to vertical dykes as shown in Figure 7. This has resulted in a complex hydrogeological setting. The groundwater compartments and zones are described in Table 2. The impact of dewatering at the Sishen pit is mainly on the fractured and brecciated banded ironstone and chert formations as well as the fractured and karstified basement dolomite [15,17]. Groundwater dewatering at Sishen Iron Ore Mine began in the 1960s [33]. Figure 8 shows the amount of water that has been abstracted to dewater the Sishen Iron Ore Mine since the late 1960s as compiled by Meyer [34] from mine and other records. The cumulative dewatering volumes are given in Figure 9. The consequence of the dewatering has been a decline in groundwater levels in the surrounding areas and in the impacted zones (Figure 7).

Figure 7: Groundwater compartments and impacted zones 2016 (Meyer (2016) as cited by Exigo [17]).

Table 2: Groundwater compartments and zones [17].

Compartment/ Description groundwater zone Sishen Mine The Sishen Mine Compartment that has been dewatered. The boundaries of this Compartment compartment are formed by an east-west dolerite dyke, two north-south diabase dykes, a northwest- southeast diabase dyke and a northeast-southwest diabase dyke. The latter dyke has been mined through and breached. This compartment is in constrained hydraulic connection with some of the neighbouring compartments. Constrained hydraulic connection means that there is no direct link across which groundwater can flow freely. The constrained flow is called leakage. The constrained hydraulic connection is due to the fact that some dykes are younger than others, notably the dolerite dyke is much younger than the diabase dykes. The younger dykes cut through the older dykes. There are also faults that are inferred to cut through some of the dykes. Sishen North- The Sishen North-Eastern Compartment that is partially impacted by dewatering. It is Eastern inferred that leakage takes place from this compartment across the diabase dyke/s to Compartment the Sishen Mine Compartment. This compartment’s western boundary is formed by the northeast-southwest diabase dyke and the northwest-southeast diabase dyke. Sishen Northern The Sishen Northern Compartment is partially dewatered. The southern boundary of this Compartment compartment is formed by the two diabase dykes (northeast-southwest and northwest- southeast dykes). The northern boundary of this compartment is formed by the Dwyka Tillite Aquitard.

Compartment/ Description groundwater zone Sishen Western The Sishen Western Compartment is partially impacted by dewatering. This Compartment compartments eastern boundary is formed by the north-south trending diabase dyke that forms the western boundary of the Sishen Mine Compartment. Leakage takes place across constrained hydraulic connections from the Western Compartment to the Sishen Compartment. The western boundary of this compartment is formed by an inferred dyke across which groundwater levels vary by 20-50 m (Meyer, personal communication). This inferred dyke has to date been intersected in one borehole but has not been yet been geophysically traced. A weak geophysical (magnetic) signature is expected due to the thick Kalahari Group cover. Sishen Far Western Groundwater conditions have not been impacted in the Sishen Far Western Compartment Compartment. This compartment is to the west of the Sishen Western Compartment and extends towards the Gamagara River and beyond. The exact western extent of this compartment and groundwater head elevations is uncertain as it is far from the Sishen Mine Compartment. Shallow upper The shallow upper calcrete and Kalahari Aquifer/s is formed by recent geological calcrete and deposits and overlies the deep aquifers. It is not constrained by the dyke boundaries of Kalahari Aquifer the deep aquifers. The shallow aquifers are separated from the deep aquifers by a thick [zone] clay aquiclude7. The clay aquiclude is continuous in the central and northern sections but are discontinuous to the south. Groundwater in the shallow aquifer seeps towards the mine within an impacted zone, which is limited to a 500 m zone from the pit boundary. The seepage does not contribute materially to the dewatering rates of the mine, as most evaporates at the pit face. A characteristic of the shallow aquifer is its low groundwater potential. Groundwater seeps to the Gamagara River Alluvial Aquifer where it contributes to hyporheic flow8. Gamagara River The Gamagara River Alluvial Aquifer forms a groundwater zone along the Gamagara Alluvial Aquifer River. This aquifer has mainly hyporheic flow below the alluvium. The vertical thickness [zone] of this aquifer varies between 10 m to ±75 m [35]. It has three sub zones. The first is the zone upstream of the Sishen Mine Compartment where the weathered/fractured aquifers (mainly BIF and dolomite) feed hyporheic flow into the Gamagara Alluvial Aquifer. The upstream zone is inferred to have a minor impact due to leakage across and above the eastern diabase dyke boundary to the Sishen Compartment. The Gamagara Alluvial Aquifer overlies the diabase dykes as it is younger. The zone of the Gamagara Alluvial Aquifer in the Sishen Mine Compartment is dewatered and does not exist in this area anymore, except during and after flood events when it can have a temporary existence. The downstream zone receives hyporheic flow from the shallow calcrete aquifer, and is not impacted directly by the dewatered Sishen Mine Compartment. The upstream zone is still recharged by Gamagara River surface flows which occurs every 5-8 years and during rainfall events. The downstream zone does not frequently receive surface flows from the upstream zone as these mainly drain into the Sishen Mine Compartment via swallet zones [35]. It is impacted in that recharge due to flood events does not reach the downstream environment, except during big flood events. The downstream impacted area in this zone has been delineated to Dibeng [36]. The downstream zone does receive surface flows from the environment downstream from the Sishen Compartment and for example from the Olifantsloop tributary. It does receive recharge from direct rainfall in between flood events.

7 A low permeability unit that forms either the upper or lower boundary of a groundwater flow system [88]. 8 Hyporheic flow is the transport of surface water through sediments in flow paths that return to surface water [89].

10 Dewatering volumes million m3/a million volumes Dewatering 5

1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 2015

Figure 8: Dewatering volumes from Sishen Iron Mine [34].

Table 3: Groundwater levels and impacted zones [17].

Groundwater levels and Description impacted zones Zone 0 - Gamagara River This area is impacted on due to the partial dewatering of the Sishen Alluvial Aquifer zone compartment. Zone 1a - Partially dewatered It covers an area of 26 300 ha and is the partially dewatered Sishen Mine Sishen Main Compartment compartment where the abstraction takes place. Groundwater levels range from depths of ±280 m in the deepest part of the mine to ±120 m on the edges of the compartment dyke boundaries. Zone 1b - Partial Impacted It covers an additional area of 28 000 ha (i.e. total area of impacted zone is 54 Groundwater Zone: 600 ha) and is the external zone beyond the Sishen Compartment from where groundwater leaks through to the compartment zone. This area is partially impacted with groundwater levels that range between 30 m and 2.5 m drawdown. The baseline groundwater levels are inferred to be variable but range between <1m – 25 m depth. Zone 1c - Local Water Supply This zone is mainly the town of Kathu (Gamagara Municipality) where Zone abstraction from the Sishen North-Eastern and Sishen Northern Compartments takes place. The municipality also receives a portion (i.e. water supplied) of the water abstracted due to mine dewatering Zone 2 – Gamagara Alluvial This is the subsurface shallow aquifer zone that is impacted on due to the Aquifer Zone swallets in the Gamagara River where water is transferred into the Sishen Main Compartment. Groundwater levels in this area used to be almost at surface as it used to be recharged by the Gamagara River. Although the Gamagara River still flows (as in January 2017) in this zone, the impact is manifested in the dry periods in between when the floods do not reach this zone. Zone 3 – Lava aquifers west This area is not well defined and there is no provable impact of mine of the Gamagara dewatering based on monitoring data Zone 4 Regional Sedibeng Water Supply Zone: This is the regional Sedibeng Water Services Provider where excess dewatering volumes in the order of 2.5 million m3/a is used to supplement regional water supply in the local catchment and towards farms and communities in the Kalahari region to the north.

600

500

400

300

200

100 Cumulative dewatering volumes million m3/a million volumes dewatering Cumulative

1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017

Figure 9: Cumulative dewatering of Sishen Iron Mine [34].

There have been numerous complaints by farmers about the impact of dewatering activities by Sishen Iron Ore Mine and these were investigated by Meyer [37–52]. The conclusions from most of the investigations were that:

 Water levels measured were in the same ranges as before the 1973/74, 1974/76 and 1988/91 high rainfall periods and before large scale groundwater abstraction occurred at Sishen Iron Ore Mine. As a result, groundwater resources have not been and are currently not impacted by the large scale groundwater abstraction performed by Sishen Iron Ore Mine in areas identified as outside the dewatering zone.  In some cases the collapse of boreholes has reduced the water inflow area significantly, and together with carbonate incrustation, is believed to be the main cause of declining borehole yields. In some of the boreholes incorrect borehole construction and incorrect pumps prevented optimal abstraction.  On the farm Curtis 470, the long-term groundwater level records as measured in the two deep boreholes CS01 and CS02 which represent the conditions in the deep aquifer below the Kalahari Group geological succession, indicate that the deep aquifer at both these locations was being impacted by recent increased mine dewatering activities associated with the northward expansion of mining activities. This conclusion confirms the observation reported in October 2013 at the meeting with the farming community that the impacted area

is believed to be expanding towards the farm Curtis and needs to be monitored closely [50].

There have been transmission losses in the Gamagara River as a result of the effects of the mining dewatering activities in the dewatering zone (Figure 10), as well as due to the swallets [12].

Figure 10: Representation of the groundwater levels in the dewatering compartment before and after dewatering activities [12].

Exigo [17] evaluated the potential cumulative impacts on groundwater focussing on expansion of the life of the mine pit and partial dewatering with consequent post- operational water supply or re-watering and pit flooding scenarios. The following conclusions were drawn [17]:

 The dewatering is expected to increase as the mine is planning to deepen the pit by 140 m to an elevation of 800 metres above mean sea level (440 m maximum depth).  The simulated groundwater inflow rate into the mine workings would be in the order of 20 million m3/a or a 20% increase. The simulated zone of influence would cover an area of 40 200 ha or a 30% increase (Figure 11). The external impacted zone is expected to shift to the west as the Doornvlei and Vliegveld West open pits would mine through the western Sishen Compartment Dyke boundary.  Increased capture of flood events. The Gamagara River has the potential to infiltrate 7 million m3/d of which almost 2.5 million m3/d (40%) is expected via swallet zones.

Figure 11: Sishen Mine Compartments and future simulated impact zones - 2032 (Itasca, 2016 as cited by Exigo [17]).

The Kolomela Mine, previously called the Sishen South Mine, is located approximately 12 km south east of Postmasburg (Figure 3). Extensive dewatering is required for mining to take place at Kolomela9 [53,54]. No studies, however, are available to consider the impact of dewatering associated with this operation on groundwater users and the environment.

Dewatering operations at Beeshoek Mine already impact on the groundwater levels in the region [53,55,56]. A lowering in water levels can be seen on the farms Kalkfontein, Kapstewel, Putjie, Aarkop, Doornfontein, the Beeshoek Game Camp and Ploegfontein [55]. However, a regional rise in groundwater level can also be observed to the west and east of the mining area and could be attributed to cessation or decrease of depressurisation and abstraction in these areas and also due to water leakages [55].

The hydraulic properties of the Khumani Iron Ore Mine area are characterised by shallow dolomitic aquifers with high transmissivities [57].

99 Kolomela Mine is considering artificial recharge to offset the dewatering effects [53,54].

The upper, semi-confined aquifer in the calcrete or at the contact between the calcrete and underlying Kalahari clay formation is poorly developed in the study area and only sustains livestock and domestic water supply [57]. The lithologies below the dolomites are characterised by interbedded chert, ironstones, chert breccias, quartzites, conglomerates and shales which would be indicative of secondary aquifers [57]. The groundwater is compartmentalised. A north–south striking structure running through the Khumani Mine property forms a barrier, and the differences in water levels on either side of the structure are notable [58]. No dewatering activities are undertaken by the mine, due to ongoing dewatering activities in the surrounding area [57].

Water for mining activities at the COZA Iron Ore Mine will be sourced from pit dewatering activities at the mine and will be undertaken by means of dewatering boreholes [59]. It is estimated that approximately 220 m3/day [80,300 m3/annum] of water will be extracted from the dewatering boreholes located at Doornpan 445. The water will be abstracted from the Kalahari Group sediments and Ghaap Group dolomites. It is expected that the maximum groundwater level drawdown will be ± 53 meters and that the cone of depression will not exceed a maximum distance of ± 500 meters from the pit with expected recovery of groundwater levels to take 110 years at the Doornpan Farm [59].

Groundwater in the Lomoteng Mine area occurs in both secondary (or fractured rock) aquifers and primary aquifers [60]. The first is formed by jointing and fracturing of the otherwise solid bedrock and limited primary aquifers occur in the dolomitic area east of the site where the groundwater level rises within the weathered zone [60]. No studies are available at Lomoteng Mine to consider the impact of dewatering on groundwater users and the environment.

There are two aquifers present at the United Manganese of Kalahari site. The first aquifer is the local calcrete aquifer and the second is the BIF aquifer which has a higher groundwater potential [61]. Dewatering does take place on site during heavy rainfall events [61]. No information about the extent of dewatering is provided.

No studies are available at Finch Mine and PPC Lime to consider the impact of dewatering on groundwater users and the environment. Both Finsch diamond mine and PPC Lime Acres are underlain by the dolomitic aquifer in which PPC Lime and Finsch mine are performing dewatering [54].

No studies are available in the public domain from Autumn Skies Resources and Logistics, Blue Dust, PMG Bishop Mine, Burk Mine, Dave Hughes Business Enterprise. Dirleton Minerals and Energy, Diro Iron Ore Mine, Diro Manganese Mine, Emang Mmogo

Manganese Mining, E&R Kadgame, Helpe bietjie, Kareepan Investments, Khudumani Manganese, Leago Mining and Infrastructure Investments, Lohatla Manganese Mining, Mashwening Iron Ore Mine, Mogotlhoho Mining, Morokwa Manganese Mine, Ringside Trading 520 Pty Ltd, Sedibeng Iron Ore Mine Lime, Sibelo Resources, Sparkle Mine, Timasani Mining and Tsantsabane Mining so as to consider the current or proposed impacts of dewatering activities on groundwater users and the environment. A number of these mines are in the pre-operational phase.

The most significant impact of the mines in the region has been the dewatering of the aquifers. The sources of water for dewatering are the BIF and dolomites of the Ghaap Group. To predict the range of possible changes in hydrogeological conditions resulting from mine dewatering, groundwater models were constructed, but these have focused on local, individual mining companies and their operations. A regional approach to groundwater modelling was not taken. Another constraint is that groundwater reports commissioned by the mines are not necessarily readily available in the public domain.

The extent of the dewatering zones of the Sishen Iron Ore Mine has been discussed by numerous authors as mentioned in the sections above and in Appendix 1. The other mines in the region have not had similar levels of detail or rigour of investigations.

The cursory analysis of the groundwater levels taken from the DWS databases show too infrequent monitoring, gaps in the database and lack of quality control to ensure that the data captured was correct (the measurements taken may have been correct at the time). The example hydrograph below shows a groundwater level taken in the 1970s, followed by infrequent monitoring in the mid-80s to mid-90s with more frequent monitoring from the late 1990s onwards. In the mid-2000s there was again a gap in the monitoring record.

Figure 12: Example hydrograph in the Sishen and Postmasburg area (NGA database).

The conclusions from the studies can be summarised as follows:

 There have been decreased flows in streams and wetlands that are in hydraulic contact with the affected groundwater body. Dewatering of the groundwater compartment underlying the Gamagara River compartment has caused higher transmission losses for small flow events than before dewatering started [13]. Increased dewatering of the aquifer system will result in increased capture of flood events.  The resulting dewatering has resulted in groundwater level declines. The zone of dewatering has been delineated by Meyer [15] and updated by Meyer (2016) as cited by Exigo [17]. MWC [31] fully agreed with the extent of the Meyer [15] dewatering cone as portrayed in his conceptual model report.  A slightly larger area in the north-western corner of the dewatering cone is the only difference in the MWC [31] interpretation compared to Meyer [15] dewatering cone.  In areas outside the dewatering cone of depression, groundwater declines are related to areas of low rainfall and resultant lower recharge taking place.

The review of information did not provide an opportunity for the analysis of primary data. The dykes delineating the compartments are impermeable to semi-permeable, except in the case where mining has breached the dykes and induced dewatering as shown in Figure 13.

4.2. Discharge and recharge areas

Identifying groundwater recharge and discharge areas across catchments is critical to implementing effective groundwater sustainability strategies. Groundwater discharge processes can include evaporation and transpiration of groundwater, and groundwater ﬂow to the surface, including discharge to wetlands and rivers, whilst locations where groundwater is not discharging are potential recharge areas for groundwater [62]. In semi-arid areas, quantification of groundwater recharge is complex because of the extreme hydrometeorological conditions. Recharge events in such environments are predominantly episodic or intermittent. This means that rainfall is contributing to recharge only during surplus rainfall events. Inspection of hydrograph responses to rainfall in semi- arid regions reveals a threshold rainfall intensity that has to be exceeded for recharge to occur [31,63]. Van Wyk [63] estimated episodic recharge events to take place in the semi-arid areas of South Africa once every five years. Thus, flood events are crucial for groundwater recharge to occur. In South Africa, recharge often takes place through preferential pathways such as faults and fractures. Based on available literature this section identifies recharge and discharge areas in the study area.

4.2.1. Discharge areas The potential indicators of groundwater discharge include a shallow water table, lower temporal variability of vegetation activity, terrain indicators such as topographic depressions and break of slope, and groundwater flow direction towards surface water bodies [62]. These discharge areas are important for ecosystems that are groundwater dependent [64]:

 Terrestrial vegetation: dependent on diffuse groundwater discharge through plant root systems where the groundwater body is within the rooting depth of the plants, also called “cryptic” discharge; most noticeable as oasis-type vegetation in arid environments.  River base flow systems: where the character and composition of the aquatic (in-stream) or riparian (near stream) ecosystem depends on groundwater discharge as base (dry season) flows. In many cases the flows also are critical for meeting human needs both directly and by sustaining human enterprises.

 Wetlands and spring systems: springs are included here because there is essentially a continuum from a spring which has a definite discharge point to wetlands which depend on diffuse discharge over wide areas. The category would apply to wetlands with a known or likely component of groundwater discharge in their hydrological cycle; at least some endorheic pans and many of the coastal wetlands are examples. Ecosystems dependent on spring discharges are also included in line with the report’s inclusion of their “mound spring” vegetation in this category.  Aquifer and cave ecosystems: The report [65] restricts this to “hypogean life” (subterranean living organisms), including those in the groundwater body itself. These are important but we believe that the potential dependency of any associated above-ground ecosystems also needs to be addressed. Areas with karst geology such as dolomitic rock systems or limestones are examples.

As mentioned previously, aquifer systems in the area under investigation have been compartmentalized and in the case of a compartment being fully saturated, springs [66] or water seeps may occur. Evidence for this can be found on the farm McCarthy where a spring yielding about 2 l/s is present [15]. However, the dewatering of the aquifer systems means that flowing springs are unlikely and baseflow is absent in the Gamagara River [13,34]. There seems to be no major visible discharge areas in the aquifer systems except for groundwater discharge to the north following the natural drainage as indicated in Figure 13. The flow gradients show the impact of high abstractions around the Sishen, Beeshoek and Kolomela Iron Ore Mines [9]. Exigo [67] based on satellite imagery made preliminary findings about possible discharge zones in the Skeifontein Spruit (Figure 14. The Gamagara River is a gaining river outside the dewatered zone. Inside the dewatered zone (Moria to Demaneng and Demaneng to Mokaning), the Gamagara River is a losing stream [12,34].

Figure 13: Piezometric Map of the D41J and D73A quaternary catchments based on the 2013 groundwater level elevations [9].

Figure 14: Local map showing the land cover with comparison between a dry (2013) and a wet (1990) year [67].

4.2.2. Recharge areas The natural groundwater drainage is from the eastern catchment boundary which is delineated by the Kuruman Hills towards the outflow area at Dibeng [9] as shown in Figure 13. The Kuruman Hills are the main recharge area of the study area [9]. Recharge of the dolomites of the Ghaap Plateau is less than 2-3% of annual rainfall [66]. Dziembowski [11] showed with his investigations that very recent recharge is evident in large tracts of dolomites in the Southern Area of the Gamagara Catchment as well as in the southern section of the Sishen compartment. Isotope observations supported the view that the Kalahari Beds provide a limited contribution to the groundwater at Sishen and that the dolomite outcrops constitute the main recharge area. Very recent water is found under confined conditions in highly conductive zones at Lylyveld in close proximity of the Sishen mine. Recent to very recent waters were also found within the mining area itself. The waters being pumped from Hill 2 showed no contribution from very recent (post bomb) recharge. This implies, at that time, that the compartment reservoir has not yet been fully turned over by pumping.

Golder [68], based on the conceptual understanding of the Vaal Gamagara groundwater system, estimated that the median regional recharge values range between 2.5 and 20 mm/a for catchment D41L .

Exigo [67] conducted a study to determine the status of the background or reference environment in terms of groundwater recharge, usage volumes and the Reserve in Catchments D41J & D73A. The groundwater yield model for the Reserve (GYMR) was used by Exigo [67] to quantify the groundwater balances within the context of the Reserve and to try and understand the system.

The total recharge for average rainfall conditions is in the order of 60 million m3/a. This reduces to around 30 million m3/a in 1:20 year drought conditions. For the specific catchments, the following conclusions were drawn [67]:

(a) The average recharge in D41 Groundwater Management Unit10 (GMUs) totals 24 million m3/a, with an abstraction rate of 20.5 million m3/a, and a surplus of 3.7 million m3/a. In total, this Quaternary catchment has a stress level of 85% based on recharge. The main stressed GMUs are D41J-G5 and D41J-G6 which classify as stressed beyond 100%. This is mainly due to mine dewatering. D41J-G7 based on recharge only is stressed to almost 50% which is due to the inferred very low recharge on the lavas. GMUs D41J-G1-4 have stress levels below 10% and should still be able to support the development of groundwater resources of at least 5 million m3/a. During drought conditions, the recharge reduces to 12 million m3/a, with a deficit of almost 8.5 million m3/a, which must be obtained from aquifer storage. (b) Recharge in the D73A+C92C-01 GMU totals 36 million m3/a, with abstraction at almost 40.4 million m3/a and a deficit of 4.4 million m3/a. The main water users are Finch Mine at 15.8 million m3/a, Kolomela at 16.8 million m3/a and Beeshoek at 4.510 million m3/a. The regional area is stressed beyond 100% if only recharge is considered. During drought conditions, the recharge reduces to 18 million m3/a, with a deficit of 22.5 million m3/a, which would be obtained from groundwater storage. GMU C92C01 would become severely stressed during drought conditions. (c) The total actual abstraction of 61 million m3/a, exceeds recharge by 1 million m3/a and a stress level of just over 100% [67]. This means that there is an overall deficit of around 1 million m3/a in average rainfall conditions, which changes to a deficit of -31 million m3/a under 1:20 year drought conditions [67]. (d) The allocated water use is in the order of 87 million m3/a, which is 27 million m3/a more than the average annual recharge and does not make provision for drought conditions with a stress level of 145%. During drought conditions, this deficit increases to more than 57 million m3/a, which must be obtained from storage.

The high rainfall and resultant floods of 1972/73 recharged the aquifers in the region resulting in significant water level increases (Figure 15; Figure 16). The 1988 and 1991 flood-rainfall events also contributed significantly to recharge resulting in an increase in groundwater levels [12]. The large variation in water levels of boreholes along the

10 An area of a catchment that requires consistent management actions to maintain the desired level of use or protection of groundwater, delineation is based on a management considerations rather than geohydrological criteria [68].

Gamagara River in the dewatered zone can only be explained by recharge emanating from surface runoff (transmission losses) in the Gamagara River [12].

Figure 15: D41J monthly rainfall 1920-2009 (WR2012) [67].

Figure 16: D73A monthly rainfall 1920-2009 (WR2012) [67].

Two recharge mechanisms of the Gamagara River alluvial aquifer can be deduced, namely recharge from surrounding aquifers (currently only outside the dewatered zone) and recharge from flow/flood events in the Gamagara River [12]. Preliminary groundwater recharge calculations based on annual recharge figures provided by VSA Geoconsultants (2006), some 60,000 m3 could have been contributed annually to the alluvial aquifer from the Kalahari sediments that have now been removed by the mining activity [34]. Recharge on a regional scale has been estimated to average ±2.5% of rainfall of 340 mm/a, which amounts to around 8.5 mm/a [67].

As discussed above, recharge to the dolomitic aquifer is intermittent taking place only during exceptional rainfall events. The groundwater level responses during these events in unimpacted areas are in most cases immediate as shown in Figure 17. However between these events groundwater recession takes place. This recession reflects the recharge minus discharge monitored at that particular location.

Figure 17: Water level vs rainfall in boreholes outside the July 2010 dewatering zone [12].

Meyer [15] compiled a simplistic cumulative annual water balance by comparing the volume of groundwater abstracted by the mine and farming activities in relation to the annual groundwater recharge over an area of 450 km2 around the Sishen Iron Ore Mine. Annual abstraction figures from 1967 for the Sishen Iron Ore Mine were used while the annual groundwater consumption by the farming and associated industries was estimated to be 150 000 m3. Cumulative annual recharge volumes were plotted against the cumulative annual volumes of groundwater abstracted [15]. The analysis showed the imbalance between abstraction and recharge which is occurring over a localized area around the Sishen Iron Ore Mine [15].

Figure 18: Cumulative groundwater abstraction compared to cumulative groundwater [15].

4.3. Groundwater use and interference

The expansion of economic activities in the area will put additional stress on groundwater resources. The intention is to continue using mine dewatering as a water supply in the future (Figure 4) but at the same time develop additional groundwater supplies to meet the water demand. Four large scale source development target areas (Figure 19) were identified with a targeted volume of 20 million m3/a [14]. Figure 20 below shows the scenarios to meet future water supply in the region. The use of water from dewatering will be utilized to implement the upgraded Vaal Gamagara Water Supply Scheme in a 5 to 7 year period as shown in Figure 20.

Figure 19: Source development areas [68].

Figure 20: Water balance - Vaal River and Source Development (SD) sources [14].

The impacts for groundwater are set to increase based on demands from the Vaal Gamagara Water Supply Scheme, mining operations, renewable energy activities and domestic water supply. The water use activities raises challenging groundwater management issues relating to the impacts of dewatering at individual mines or wellfield abstractions and the cumulative impacts of progressive development on local and regional groundwater resources such as the dolomite aquifer system.

There are various competing uses for the groundwater in the region as explained above (Figure 4, Figure 20). This includes water for the environment. In the past decade mining increased from 3 to 37 mines, 2 new solar power plants were erected and the population increased by 21% within 5 years [8]. There are concerns from stakeholders that water use licenses are issued without due regard of the cumulative impact of these abstractions on the groundwater resources. The catchments are in water stress as the summary of Reserve determination shows in Table 4.

Table 4: Summary of Golder detailed Reserve determination11 (2015) volume in Mm3/a as cited by van Dyk [8].

Quaternary GMU Total inflow Ave annual large Stress Index Compare PESC Catchment/-GMU or recharge scale [Re ⁄Abs] estimate abstractions D41J-G1 5.14 Low: <60% C D41J-G2 4.92 Low: <60% C D41J-G3 7.80 2,022,700 High: >100% F D41J-G4 1.10 Med: <100%-60% D D41J-G5 0.0 Low: <60% B D41J-G6 10.44 13,412,100 High: >100% F D41J-G7 3.13 Low: <60% C TOTAL 32.6 D73A-01 0.95 Low: <60% C D73A-02 4.56 Low: <60% C D73A-03 3.98 Med: >60% D D73A-04 2.25 Med:<100%->60% D D73A-05 3.29 Low: <60% C D73A-06 3.21 11,133,016 High: >100% F D73A-07 0.49 Low: <60% C D73A-08 1.56 Low: <60% C D73A-09 4.01 Low: <60% C TOTAL 24.3

11 There seems to be discrepancy in the stress index calculated for the Quaternary Catchments between the Golder 2015 report as cited by Van Dyk [8] and Exigo [54] report.

There are a number of solar projects planned in the region (Table 5). Solar photovoltaic (PV) and wind energy exhibit the lowest demand for water, and could perhaps be considered the most viable renewable energy options in terms of water withdrawal and consumption [69].

Table 5: Solar power plants and their water requirements.

Solar Plant Water use requirement (m3/a) Adams Solar PV Project No information Agulhas – Hotazel Power Plant No information Jasper Solar Park 500012 Redstone Thermal Power Plant 250,00013

The water consumption footprint will be dominated by demand from the mining sector, followed by Local Municipalities, agricultural sector and power generation. The challenge remains not only to provide adequate volumes of water for local economic development but also taking into account spatial and temporal requirements.

4.4. Cumulative impacts

The presence of an open cast mine in close proximity has a profound influence on the groundwater regime. The previous sections have predominantly focussed on Sishen Iron Ore Mine and the established mines as the largest users of groundwater in the region. The development of new open cast mines in the region will be another stressor on the groundwater system. There will be water demands for both production and potable water supply and also surplus water management, amongst a range of water management issues. Assessment of possible changes in hydrogeological conditions requires regional assessment methodologies and perhaps multiple integrated numerical models. Due to data scarcity, groundwater modellers often neglect the hydraulic interference of neighbouring mines and their cumulative impacts on the groundwater resource [70]. However, assessing for example the groundwater table drawdown for a single mine only while neglecting the impact of neighbouring mine developments on the same aquifer results in unrealistic mine inflow and drawdown estimates and subsequently flawed groundwater management decisions or environmental impact assessments [70]. The absence of regional studies makes it difficult to understand the implications of large-scale groundwater abstraction.

Mining for iron- and manganese ore will leave a legacy of open pits which will form pit lakes once mining below the water table ceases. Pit lake waters are typically contaminated with metals, metalloids, saline, acidic or alkaline properties, and rarely

12 Unsigned agreement between Sedibeng Water and Jasper Power Company 13 Letter from Sedibeng Water re Water Supply to Redstone Solar Thermal Power Plant (Humansrus site)

32 approach natural waterbody chemistry (Kumar et al. 2009 as cited by WA EPA [71]). Exigo [17] evaluated re-watering and pit flooding scenarios for the Sishen Ore Mine. The simulation results indicated that it would take between 75 - 150 years for the pit to flood to levels of 1,040 – 1,070 metres above mean sea level with a pit volume of ±400 million m3. In the absence of understanding the cumulative impacts on regional hydrogeology, management decisions regarding water resources becomes doubtful.

The impact of climate change and resultant impact on recharge and discharge functions at a scale appropriate for decision-making for groundwater resources has not been modelled at catchment level.

Limited studies have been conducted to understand the cumulative implications of mine dewatering and large-scale abstraction on competing groundwater users. The dewatering of the dolomite aquifers for gold mining (e.g. Carletonville (Far West Rand) Gold Field) provides a harsh reality of cumulative implications. To date, investigations have been at mine- or user-level scale and rarely conducted in a regional context. Some of the regional interferences include:

 Drawdown interferences at distance from the open pit mines;  Lowering of the groundwater levels impacting on various receptors including groundwater users and the environment; and  Continued river water losses and capturing of flood water after closure of mines.

These and other impacts require quantification to put “sensible” mitigation strategies in place for water resource management to minimise the impact on groundwater users and the environment. This includes:

 Adoption of water stewardship principles to minimise harm on the environment;  Allocation of water use licenses based on a scientific allocation plan for the region, also taking into account post-closure implications of mine pit lakes forming;  Implementation of strategies such as artificial recharge, beneficial use of the water; and  Dealing with surplus water and minimising water quality impacts.

5. DISCUSSION

The current use of groundwater is unsustainable. In the catchments there are competing demands for groundwater consumption, water supply for domestic and industrial use and for agricultural purposes [9]. The management of the groundwater resources must take into consideration not only technical issues but also socio-ecological aspects [3]. The framework categories identified in Table 6 were adapted to the local situation to analyse the sustainability provisions for groundwater management in the region. In undertaking this analysis, any areas where parts of the sustainability provisions are not addressed represent a ‘gap’. The analysis reflected in the table was based on numerous sources of information provided which were compiled, reviewed, and mined using a framework analysis [72]. Each of the identified gaps was categorised and colour-coded (Table 6) to reflect the magnitude of the gap: (a) green (3) – criteria are met; (b) amber (2) – criteria partially met; (c) red (1) – significant gap or absent.

Table 6: A framework for analysis of sustainability provisions [1–3].

14 This is scale dependant as most of the numerical models are done at local scale rather than regional scale.

Capacity Criterion Context Gap Legal and Water well drilling permits & For large users, with interests of small 2 institutional groundwater use rights users noted Instruments to reduce groundwater Water well closure/constraint in critical 1 abstraction areas Instruments to prevent water well In overexploited or polluted areas 1 construction Sanction for illegal water well operation Penalizing excessive pumping above 1 permit Groundwater abstraction & use ‘Resource charge’ on larger users 1 charging Land use control on potentially polluting Prohibition or restriction since 2 activities groundwater hazard Levies on generation/discharge of Providing incentives for pollution 1 potential pollutants prevention Government agency as ‘groundwater Empowered to act on cross-sectoral 2 resource guardian’ basis Community aquifer management Mobilising and formalising community 2 organisations participation Cross-Sector Coordination with agricultural, mineral Ensuring ‘real water saving’ and Policy and social development pollution control 2 Coordination Groundwater based urban/industrial To conserve and protect groundwater 2 planning resources Compensation for groundwater Related to constraints on land-use 2 protection activities Operational Public participation in groundwater Effective in control of exploitation and 1 management pollution Existence of groundwater management With measures and instruments agreed 2 action plan

This systematic analysis has highlighted gaps that need to be addressed to support sustainable development of groundwater resources in the region. These indicators point to the following priority interventions but should not be viewed as a checklist [1]:

(a) Monitoring or calculating the changes in the aquifer water balance or dynamic equilibrium, and comparing these to initial estimations: i. changes in the pre-abstraction aquifer discharge ii. changes in the pre-abstraction aquifer recharge iii. changes in the pre-abstraction aquifer storage (b) Monitoring or calculating any other observed changes in aquifer conditions, and comparing these with initial estimations (c) Monitoring or calculating progress towards a new dynamic equilibrium and updating the initial estimation of recovery time.

The legal and institutional frameworks in place do not adequately deal with local conflicts and mediation processes. The absence of an integrated regional study makes it difficult to understand the implications of large-scale groundwater abstractions on competing users meaning that water use licenses are issued without a proper understanding of the cumulative interferences of different users and their dewatering requirements and impact.

A necessary facet of direct regulation is a system of inspection and enforcement, including adequate resources for [licence] review, inspection of specific sites, and some form of penalties against developers who violate the conditions of their licences (IRGC, 2013). However, the current challenges and workforce capacity limitations in DWS associated with processing and issuing of licence applications may hamper progress [3].

6. CONCLUSION

The most significant impact of the mines in the region has been the dewatering of the aquifers of the BIF and dolomites of the Ghaap Group. To predict the range of possible changes in hydrogeological conditions resulting from mine dewatering, the mines have constructed groundwater models but this has been specific and aimed at individual mining companies and their operations instead of taking a regional approach. Another constraint is that the groundwater reports were commissioned by the mines and are not easily available in the public domain. The extent of the dewatering zones, of the Sishen Iron Ore Mine has been investigated extensively, whilst the other mines in the region, to the author’s knowledge and from assessment of the available literature, did not carry out investigations at the same level of detail.

Groundwater discharge processes include evaporation and transpiration of groundwater, and groundwater ﬂow to the surface, including discharge to wetlands and rivers. In semi- arid areas quantification of groundwater recharge is complex because of the extreme hydrometeorological conditions. Recharge events in such environments are predominantly episodic or intermittent. This means that rainfall contributes to recharge only during surplus rainfall events. The dewatering of the aquifer systems means that springs are not likely to flow and baseflow is absent in the Gamagara River. There seems to be no major visible discharge areas in the aquifer systems except for possible discharge zones in the Skeifontein Spruit. The natural groundwater drainage is from the eastern catchment boundary (recharge area) in the east (Kuruman Hills) towards the outflow area at Dibeng. Recharge can be local and indirect and is also induced as a result of the dewatering activities. The Gamagara River is a gaining river outside the dewatered zone. Inside the dewatered zone (Moria to Demaneng and Demaneng to Mokaning), the Gamagara River is a losing stream. The abstraction exceeds sustainable rates.

The absence of an integrated regional study makes it difficult to understand the implications of large-scale groundwater abstractions on competing users. There are concerns from stakeholders that water use licenses are issued without due regard for the cumulative impact of these abstractions on the groundwater resources. The catchments are in water stress (see Reserve determinations). The water (consumption) footprint will be dominated by the demand from the mining sector, followed by Local Municipalities, agricultural sector and power generation. The challenge remains not only to provide adequate volumes of water for local economic development but also to take into account spatial and temporal requirements. Limited studies have been conducted to understand

37 the cumulative implications of mine dewatering and large-scale abstraction on competing groundwater users.

An approach similar to a strategic environmental assessment is required to analyse the cumulative impacts of large-scale groundwater dewatering and abstraction on groundwater users and environment. The groundwater resources and particularly the dolomite aquifers are at risk of being dewatered unless responsible groundwater management is practised and regulations are enforced.

Based on the evaluation of numerous reports and the gap analysis, I would recommend to:

 Establish a groundwater monitoring network that takes into account monitoring of recharge and discharge areas;  Establish a standardised regional digital relational database that combines data from all water users. The design should accommodate for all monitoring points, all categories of data and different data collection scheduling (frequency), and include historical data. Use of a common database will facilitate comparison among different sites.  Access to the common database for all water users; and  Develop a regional integrated numerical model(s) to address the gaps identified in the framework analysis.

In conclusion, a technical-institutional model is required that facilitates decision-making and trust amongst all stakeholders.

7. ACKNOWLEDGEMENTS

Mr Hoffmeyer Joubert from Agri Northern Cape is acknowledged for initiating the project. The report was internally reviewed by Dr Hans Beekman. The external reviewers are thanked for their critical and constructive comments:

 Dr Shafick Adams  Phil Hobbs  Gawie Van Dyk

8. REFERENCES

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APPENDIX 1: REVIEW OF MINE AND RELATED WATER REPORTS

Mine water reports provided by Mr. Hoffie Hoffmeyer were reviewed and a compendium of the different reports’ conclusions is provided in the table. Reports done for Sishen Ore Mine dominate the compendium.

Mine name Report Summary of the conclusions of the report Beeshoek Iron GPT [55]. 2013 Hydrocensus GPT was appointed by Assmang Limited conduct a Ore mine survey and the interpretation hydrocensus study on and around the Beeshoek Iron Ore of data in the Postmasburg mine. A total of 135 boreholes were visited during the area for Beeshoek Iron Ore hydrocensus of 2013. Water samples were collected from Mine Postmasburg. selected boreholes to evaluate the hydrochemical character and changes in the aquifer. Comparison of water levels from the 2002, 2005, 2010 and 2013 hydrocensus studies was performed to evaluate changes. GPT observed a lowering in water levels on the farms Kalkfontein, Kapstewel, Putjie, Aarkop, Doornfontein, the Beeshoek Game Camp and Ploegfontein. However, a rise in groundwater level was also observed. This rise observed to the west and east of the mining area was attributed to cessation or decrease of depressurisation and abstraction in these areas. Bekker [73]. Beeshoek Iron Bekker conducted an annual performance assessment in Ore Mine; 2015 Annual terms of the National Water Act and found non- Performance Assessment in compliance to section 21(a; j) water uses. Various terms of the National Water boreholes exceeded the volumes of water to be Act, 1998 [73]. abstracted and some pits that are being dewatered are not included in the existing WUL. Bestwood Estate Golder [74] Report on Golder established an Information Management System groundwater database for the Bestwood Estate that maintains a database on developments for the water supply, distribution and delivery infrastructure. Both Bestwood Estate, Near Kathu, groundwater quality (hydrochemistry) and quantity (water Northern Cape Province levels and volumes pumped) data are covered and graphic format allows trend analysis procedures in the database configuration. Finsch Diamond Vermeulen, D and Lourens, P Finsch Diamond Mine (Petra Diamonds) contracted the Mine [75,76]. Groundwater Institute for Groundwater Studies at the University of the Monitoring Report for Finsch Free State to perform water monitoring on 61 boreholes Diamond Mine (Petra (depending if accessible) and 11 surface structures at the Diamonds) mine. Most of the water levels remained sideways since 2007. The exceptions are as follows (a) the boreholes on the western side of the pit all indicate a rising trend in water level except for boreholes E17, E31, G8 and G12. The water levels of the three boreholes (G9 to G10) situated on the farm Rocky Flats, rose between six and nine metres since they were last measured in 2011, this should be monitored closely; (b) Borehole E21, situated on a topographic high, rose with approximately 26 m since 2007, whereas borehole E18 situated adjacent to the mining pit dropped with approximately 16 m since 2007; (c) borehole E19, situated adjacent to the Pre-79 CRD, dropped with approximately 11 m over the past year, whereas, borehole E28 which is situated adjacent to the sewage farm dropped with 13 m since November 2013, this will be monitored.

The water levels clearly illustrate the areas of artificial recharge, i.e. the Old FRD dams, the Golf Course as well as the Britz FRD, which have shallower water levels than the rest of the boreholes. The water levels of the boreholes at the main waste rock dump on the western side of the mine are deep (70-120 m) and those to the south of the Post-79 Course Residue Deposit deeper than 120 m.

Mine name Report Summary of the conclusions of the report The water level contours illustrate the pattern of shallower water levels in the eastern area and just south of the Britz FRD and deeper water levels in the west, with the deepest towards the south of the mining pit. Khumani Iron GPT [77]. Evaluation of the GPT was tasked to conduct a thorough evaluation of the Ore Mine hydrogeological data at geohydrological situation and develop a sound Khumani Mine and the groundwater management plan for the Khumani Iron Ore development of a groundwater Mine. Dewatering had occurred before the initiation of management plan mining at Khumani mine and that some farmers have been affected. Khumani has not yet intersected the water table during its mining activities. Due to the aquifers being previously dewatered, the intersection of the water table will take longer than if no previous abstraction had taken place. It has become apparent that the effects of compartmentalisation are in effect in the project area, these effects are to be monitored closely. A north–south striking structure runs through the mine property and forms a barrier, where the differences in water levels can be seen. This is more evidence that the effects of compartmentalisation are in effect. The permeabilities of the structures forming these compartments are questionable as faulting and weathering can compromise the permeabilities. Kolomela Mine Clean Stream Scientific Clean Stream Scientific Services was commissioned to Services [78]. (2012). Annual conduct an annual hydrocensus investigation on the Hydrocensus Report privately owned farms surrounding the Kolomela Mine (previously the Sishen South Exploration Project), near Postmasburg in the Northern Cape Province. Several farms were targeted for this investigation, namely: Sunnyside, Wildealsput, Kappieskaree, Bonnetsfontein, Kameelfontein, Kameelhoek, Soetfontein, Voëlwater, Bermoli, Brand, Klipbanksfontein, Grasvlakte, Witboom, Olynfontein, Geelbult, Kalkfontein, Aucampsrus, Floradale, Koeispeen, Heuningkrantz, Broomlands and Lucasdam. The hydrocensus focuses on establishing base-line water-level and hydrochemical data on the farms surrounding the Kolomela Mine site. Water-levels remained stable (fluctuated by less than 1 meter) at most monitoring localities when comparing the March 2011 and 2012 water-level measurements. At the majority of localities, the water-levels showed varying degrees of decline, most probably attributable to conditions returning to normal after the substantial rise in the water-table recorded in 2011 after the heavy rains experienced by the region. At 30 localities, water-levels measured lower by more than 1 meter whereas a rise by more than 1 meter was recorded at 24 localities. Only two localities (Au09 and Vw04) had water-level rise by more than 5 meters since 2011 (Au09 rose by 7.42 m and Vw04 rose by 10.95 m). The exact reason for this drastic rise cannot be determined at present. At three localities (KK2, SF6 and KH12), a significant fall in water-level of more than 5 meters were recorded. The reason/s for these variations in water-level can only be determined with further investigation. Aquatico Scientific. [79].. Aquatico Scientific was commissioned to conduct an Annual Hydrocensus Report annual hydrocensus investigation on the privately owned farms surrounding the Kolomela Mine (previously the Sishen South Exploration Project), near Postmasburg in the Northern Cape Province. Several farms were targeted for this investigation, namely: Sunnyside, Wildealsput, Kappieskaree, Bonnetsfontein, Kameelfontein, Kameelhoek, Soetfontein, Voëlwater, Bermoli, Brand, Klipbanksfontein, Grasvlakte, Witboom, Olynfontein, Geelbult, Kalkfontein, Aucampsrus, Floradale, Koeispeen, Heuningkrantz, Broomlands, Lucasdam, Grootpan, Vleiput and Lynput. When comparing water-levels measured in March and May 2014 to February 2015, the water levels remained stable (fluctuating by less than 1 meter) at 69% of the monitoring boreholes. The remaining 31% the water-

Mine name Report Summary of the conclusions of the report levels showed varying degrees of decline and can be attributed to various impacts. The water-level at 34 localities measured lower by more than 1 meter where a rise by more than one meter was recorded at 4 of the localities (SF9, LD1, LT10, and LT11). Four localities had a water-level fall of more than 5 meters with the most significant drop of 15.49m and 11.12m at WIT1 and OF8 respectively. The cause/s of these drastic variations can only be determined by further investigation. Aquatico Scientific was commissioned to conduct an annual hydrocensus investigation on the privately owned farms surrounding the Kolomela Mine near Postmasburg in the Northern Cape Province. Several farms were targeted for this investigation, namely: Sunnyside, Wildealsput, Kappieskaree, Bonnetsfontein, Kameelfontein, Kameelhoek, Soetfontein, Voëlwater, Bermoli, Brand, Klipbanksfontein, Grasvlakte, Witboom, Olynfontein, Geelbult, Kalkfontein, Aucampsrus, Floradale, Koeispeen, Heuningkrantz, Broomlands, Lucasdam, Grootpan, Vleiput, Lynput, Putjie, Aarkop and Makganyene. When comparing water-levels measured in February 2015 to February 2016, the water levels remained stable (fluctuating by less than 2 meters) at 89% of the monitoring boreholes. The remaining 11% the water-levels showed varying degrees of decline and increases which can be attributed to various reasons. The water-level at 11 localities measured lower by more than two meters (KK03, KBF01, KBF02, KBF05, FD07, KH13, KH17, HK03, LT01; PE02 and PE04) where a rise by more than two meters was recorded at 10 of the localities (KMF06, AU02, KH10, AP01, AP02, AP03, AP05, AP07, AP10 and AP11). Two localities had a water-level decrease of more than 5 meters with the most significant drop of 6.23m and 9.80m at KK03 and PE02 respectively. The cause/s of these drastic variations can only be determined by further investigation. Significant water level >5 m increases were recorded at the farm Aarkop at AP01 (9.56 m) and AP02 (9.21 m). Lomoteng Mine SRK [60]. Lomoteng Mine: Based on the information discussed in the report the Hydrocensus and following was concluded regarding the groundwater Groundwater Assessment conditions at Lomoteng: Report, Northern Cape  Local geological observations during the Province. hydrocensus and lineament mapping from Google Earth images indicate numerous lineaments in the area. Many of these are partially covered by windblown sand and rather hard to identify in the field.  The area west of the mining area is largely covered by recent sediments which obscure most lineaments in this area. These sediments and the weathered bedrock underneath it form a significant primary aquifer.  Maximum immediate yields of successful boreholes drilled in the area are generally <4 ℓ/s. Boreholes drilled away from structures in solid bedrock normally yield <0.5 ℓ/s. Boreholes only intersecting the primary aquifer normally also yield <0.5 ℓ/s  High yielding boreholes 01, 04 and 10 are all linked to fracture zones or the extensions thereof.  Groundwater levels vary largely through the area from artesian to >40 mbgl. A distinct decline in the groundwater level is noted at the dolomite/quartzite contact on the far eastern side of the mining area.  Relative little groundwater is abstracted from this area and groundwater on adjacent properties is exclusively used for stock watering and domestic purposes. No irrigation occurs in the surveyed area.  Most of the calculated groundwater abstraction occurs at the proposed mining area.  The amount of water available under General Authorisation for this Quaternary Drainage Region

Mine name Report Summary of the conclusions of the report (D41J) is listed under Zone A of the Groundwater Taking Zones. Therefore, if the water demand of the mine is to be satisfied from the groundwater resources, a Water Use Licence Application will have to be submitted.  Groundwater quality in the surveyed area is generally good to very good and only deteriorates near pollution sources like kraals, soak away pits, etc. The best quality groundwater occurs near the higher laying recharge areas.  From a groundwater point of view the proposed mining site is favourable as long as possible sources of groundwater pollution are kept away from lineaments and the shallow groundwater levels of the dolomitic areas along the far eastern boundary of the prospecting area. The groundwater level in the area west of the mine pit varies between 21 and 41 mbgl.  The yield test data indicate that transmissivity values range between 7.7 and 13.7 m2/d.  Storativity values for the three yield tested boreholes vary little between 1.51 x 10-3 (borehole 10) and 1.98 x 10-3 (borehole 09) with an average value of 1.7 x 10-3.  Groundwater recharge calculations indicate that the expected water demand from the proposed mine is only ~45% of the UPGEP of the Lomoteng GRU. Therefore the proposed abstraction will likely not have a significant negative influence on groundwater levels in the area. Sishen Iron Ore Smit [66]. Smit [33] conducted an investigation in the Sishen Mine Mine Grondwatertoestande in area to understand groundwater conditions. The past 16 omgewing van Sishenmyn, years, prior to the report, water has been abstracted at a Distik Postmasburg rate of 432 x 103m3/a resulting in a drawdown of 10.7 m. The water levels have recovered indicating lateral inflow of groundwater from the dolomites as noted by Smit [33]. Initial dewatering was from the younger fractured rock formations. Dziembowski et al [11]. Dziembowski et al [11] was a multi-parameter Groundwater Studies in the environmental isotope groundwater study in Gamagara Gamagara Catchment catchment. The report incorporates previous studies by Dziembowski et al [80–82] since 1974. The following conclusions were made by Dziembowski et al [11] related to the Sishen Iron Ore Mine and surrounding areas:  In the dolomites to the south and south-east and the andesite to the south and south-west groundwater are almost exclusively recent to very-recent on the basis of the 14C and 3H concentrations. Along with indications that the dolomite is deeply karstified and that the weathering of the andesite is shallow and localised, it can be concluded that only the former will significantly contribute to the recharge of the groundwater inventory.  Moving in towards Sishen from the southern and southeastern dolomites 14C and 3H concentrations drop as the water becomes more confined. However, recent (~80% mc) waters apparently the product of natural underflow, are found under confined conditions at Lylyveld, in close proximity to the Sishen [Iron Ore] Mine.  The upper aquifer of the Kalahari Beds usually has very low yields of very recent (~100% mc, several TU) waters. Lower claybound gravels provide yields of maximum 20 m3/h, of older waters. They act as a confining layer to the high yielding pre-Kalahari formations and may carry water from these aquifers.  Pumper water from Hill 2, Sishen Mine, shows increase 14C concentration with increasing pump rate. A model suggests that at least two components contribute to the groundwater system.  The 14C and 3H concentrations suggest that the two

Mine name Report Summary of the conclusions of the report components of the mixture are (a) older storage within the Sishen compartment and (b) a more recent component at about 80% mc, a value found in high-yielding holes to the south-east of Sishen.  In groundwater systems with natural outflow (springs) it is possible to use radiocarbon and/or tritium for reservoir capacity calculations. At Sishen, the disturbance created by pumping is the only means by which to assess the behaviour of the groundwater. The tritium concentrations of the Hill 2 pumped water remains at measurable limit. None of the high tritium very recent waters found in the dolomites to the south and south east, have reached Hill 2.  The arguments above, lead to the conclusion that the water in Sishen compartment has not yet been fully turned over by pumping. Without involving any assumptions it is concluded that the total output of Hill 2 up to December 1978 represents a minimum storage of 57 x 106m3 for the compartment. Taking the area affected by dewatering as 60%, the minimum storage of the compartment is 95 x 106m3, in good agreement with the estimate of 106 x 106m3, based on loss of storage.

North and south mine groundwater are contrasted by the following observations [11]:  The concentration of 14C at Hill 2 is at present about 15% mc higher than in the dewatering holes at north mine. The response of 14C to pump rate at north mine is exactly the opposite of the Hill 2 response i.e. concentrations decrease with increasing pump rate.  The D – 18O signature for the north mine water is distinct from the Hill 2 water. Although the difference is rather small, the large amounts of water pumped and the constancy of the Hill 2 results, make it a significant distinction in origin.  Recent waters are present in the calcretes at north mine, as well as on the dyke dividing north and south mines. North mine dewatering holes do not draw in major contributions from these waters.  All isotopic evidence, as well as the different responses of the hydrographs to pump rate, indicates that the north and south mines act as individual hydrologic entities. The dividing dyke therefore appears to be an effective aquiclude, which can be made use of in dewatering planning, especially in the context of the present need for water conservation. Golder investigations Golder [83] conducted a hydrocensus to understand the impact of mine dewatering at the Sishen Iron Ore Mine. The water levels have been lowered to up to 110mbgl in the NW of the current mining area and to the south of the mine south of the R27. Dewatering of up to 10m has affected the area up to 10km NW and 16km south of the centre of the mine. The extent of the dewatering impact is controlled by the distribution of the geology and structure of the area. Three main compartments which have been affected by the dewatering are recognised.

A study to delineate dewatering cone of Compartment A was carried by Golder [84]. Sishen Ore Mine required further confirmation in the area south of the main road to Olifantshoek and west of boreholes G010 and G040 where there is a wide area lacking water level data. The study confirmed:

 The geographical extent of the impact zone caused by the mine dewatering extends approximately 20 km to the south of the centre of the mine.

Mine name Report Summary of the conclusions of the report  The area impacted is controlled by the presence of the two sub-parallel N – S trending dykes approximately 10 km apart, and the major W – E trending dyke 20 km south of the mine.  Water levels decrease rapidly towards the mine across the boundary dykes, from about 12 m below surface to >120 m below surface within the impacted zone.  Groundwater quality is good and there is no evidence of pollution.

Golder [19] conducted a dewatering study for Sishen Iron Ore Mine. The boundary delineation study has been undertaken to confirm the extent and boundaries of the area to the E and NE of the mine impacted by dewatering. In summary the study concluded:

 The dolomite aquifer is bounded by the N – S striking Sekgame dyke that is located approximately 8 km E of the mine.  The Sekgame dyke intersects the Kathu dyke within Kathu town, some 2.5 km further east than previous studies had suggested. The Kathu dyke does not provide any barrier to groundwater flow towards the mine west of the Sekgame dyke intersection.  The Dwyka does not provide a barrier to groundwater flow towards the mine in the vicinity of the Kathu dyke.  The dolomite aquifer is dewatered under Kathu town west of the intersection of the Sekgame dyke with the Kathu dyke.  The shallow Kalahari aquifer has not been impacted by the dewatering of the underlying dolomite due to the impermeable clay layer. However, a local impact can be anticipated close to the open pit where the Kalahari aquifer is mined through.  The small area of banded iron formation aquifer west of the Sekgame dyke has also not been dewatered; this is due to the presence of the impermeable basal mudstone horizon.

The Phase III study conducted by Golder [85] dealt with the area to the west and northwest of the current open pit, impacted by dewatering. The investigation programme included (a) desk study; (b) remote sensing; (c) field mapping; (d) hydrocensus; (e) geophysical survey; (f) drilling; (g) test pumping; and (h) water samples. The study confirmed:

 The geographical extent of the impact zone caused by the mine dewatering extends approximately 2 km to the west and north of the current edge of the mine.  The area impacted is controlled by the presence of the SW – NE trending dyke to the SW of the mine, the N – S trending dyke approximately 2 km west of the mine, and the W – E trending tillite valley 5 km north of the mine.  Water levels decrease rapidly towards the mine across the boundary dykes, from about 10m below surface to >174m below surface within the impacted zone.  The groundwater quality is good and there is no evidence of pollution.  The study confirms the dewatering influence around the NW Compartment is not as widespread as in southern compartment.  No privately owned property is currently being impacted.

Mine name Report Summary of the conclusions of the report Lasher and Nel [30] was appointed by the Department of Water Affairs and Forestry to evaluate a report by Golder Associates [85]. The following conclusions were made:

 The tests conducted in the Golder [85]report to evaluate the geological boundaries were inconclusive due to recovering water levels, short test times and long distances between production and observation boreholes.  The literature review indicated that most of the dykes as well as the Dwyka are not boundaries to groundwater flow under natural conditions, or current flow conditions. Water level data confirms that there is a definite decrease in water levels north of the Dwyka. Unfortunately no usable data is available towards the southwest to prove or disprove the impact of the mine.  The Golder [85] report partly defined the extent of dewatering. Considering the geological cross sections, lineaments and water level contours Lasher and Nel [33] concluded that the cone of depression extends outside the property of Kumba Resources towards the southwest and the north of the mine. Golder [9]. Development and This project included a situational assessment of the Implementation of groundwater conditions and use in the D41J and D73A Groundwater Management quaternary catchments in the Lower Vaal Management Plan in D73A and D41J Area in the Northern Cape Province. Quaternary Drainage Regions - Preliminary Draft This project presented the development of a mechanism to improve the management of the quaternary catchments water resources, assessing the current groundwater conditions (impacts on quantities and qualities) and create a platform for all interested and affected water users to participate in the long-term management of the resource.

The groundwater management plan is based on the following important clusters:

 A groundwater monitoring programme and network (i.e. a representative network) and procurement (i.e. maintenance and logistics ) framework managed by the water users and regulated by DWS –this will represent a baseline monitoring programme and a set of verified compliances (supported by the WUL conditions);  A groundwater monitoring committee consisting of water users and technical experts which represents a platform for all affected parties to address critical water resource issues and instruct special advisory services;  A groundwater database and information platform managed by the Tshiping Water Users Association and supported by all water users and regulators – directly or indirectly;  An updated groundwater conceptual model indicating the groundwater resource situation and identifying impacted management units where special case studies/monitoring is required;  Evaluation/updating of resource directed measures (evaluation of intermittent reserve, groundwater classification status and resource quality objectives);  Implementation of a catchment wide information platform that feed important water resources related issues to the interested and affected parties on a biannual interval; and  A water use licensing reporting system linked to the information platform and based on annual updates of WUL audits via the regulators.

Mine name Report Summary of the conclusions of the report Pulles Howard de Lange PHD [13] investigated a subsidence feature (also known investigations as a swallet or sink) which formed in and close to the river bed of the ephemeral Gamagara River south of the Sishen Iron Ore Mine. The study consisted of a number of components, which have all been integrated into a coherent assessment [13]:

 Hydrological (surface water) investigation – undertaken by a hydrologist from the CSIR.  “Ground movement” feature (colloquially referred to as a “sinkhole”) investigation – undertaken by VGIConsult-Geohub, Dolomite Risk Management Specialists.  Geohydrological (groundwater) investigation – undertaken by a geohydrologist from the CSIR.  Ecological (fauna and flora) investigation – undertaken by Ecosun cc and a botanist from UCT.  Public participation – undertaken by Pulles Howard and de Lange (PHD).  Project management and integration – undertaken by PHD.

In terms of the hydrological study, the following conclusions were made by PHD [13]:

 Dewatering of the groundwater compartment underlying the Gamagara River compartment has caused higher transmission losses for small flow events than before dewatering started.  The development of the subsidence features and divergence of surface flow to groundwater means that small flows, below 4 million m3 at least, are retained within the groundwater compartment. On the basis of the hydrological modelling, at least two of these events should occur every year, on average (although several may occur in a wet year and none in a drier year). It is these smaller events which would keep the Gamagara River groundwater system near the Sishen mine in balance in its natural state, but which has now been disturbed by dewatering. The impact diminishes with distance downstream. These effects of flow capture are less significant for large flow events, of the order of flow volumes of 10 – 100s of million m3 per event.  A caveat of this study is that the timing, size and number of small floods estimated by the hydrological model have inherent errors, caused by limited available data and the difficulties in modelling in arid ephemeral river systems. For example, the model may simulate small floods when in fact there are none – this is a problem of the internal structure of the model. Floods may have been observed in the Gamagara River, but the model fails to replicate the event. This is a problem relating to the small number of rain gauges in the region, which are too widely spaced to record some of the intense but highly localised storms.  The simulated small flow events (~ 5 million m3 per day or less) have bigger relative errors associated with them, but the size of these errors cannot be determined. Yet small flows are important in the natural hydrology of the Gamagara River as mentioned above. This aspect of the hydrology of the system, as well as the impact of varying soil moisture content and saturated hydraulic conductivity along the Gamagara River channel, needs further work.

In terms of the geohydrological investigation, the main conclusions reached include the following [13]:

Mine name Report Summary of the conclusions of the report  The most comprehensive historical record of flow in the Gamagara River since the start of the 20th century has been compiled.  An alternative to the traditionally accepted erosional palaeo-valley geological model for the development of the Gamagara River valley where it crosses dolomitic terrain south of the mine is proposed. According to this model deep groundwater circulation through geological times played a dominant role in the eventual development of an up to 80 m deep valley currently filled with presumably unconsolidated to semi consolidated material such as gravel, boulders, calcrete, conglomerate, clay and sand.  No evidence was found that the subsidence feature that developed at the old golf course is directly related to the presence of shallow dolomite with karst-type development.  A number of up to now unknown fractures and smaller subsidence features within the dewatered southern compartment and along the bed of the Gamagara River were identified and mapped during field surveys.  No major man-made river diversions that would alter the flow path of the Gamagara River significantly or promote the formation of subsidence features were identified.  A re-assessment of the initial interpretation of additional detailed geophysical profiles at the subsidence feature concluded that there is no evidence provided by the geophysical data to support the proposed presence of a large cavity below the Gamagara riverbed at shallow depths in the vicinity of the old golf course. It was initially supposed that such a large cavity could have a significant impact on nearby infrastructure such as roads and the railway line associated with the Sishen Iron Ore Mine ore transportation to Saldanha.  A permeability of ~1 m/day for the upper approximate one metre alluvium in the river bed was established from a series of infiltration tests.  No evidence of springs associated with the Gamagara River, except those in the upper reaches of the river at Ga Thlose, Macarthy and Lohatla, could be traced. Given the deep water levels currently experienced in the Southern compartment and also relatively deep water levels in the alluvial aquifer associated with the Gamagara River, it is unlikely that any flowing springs will be present under these conditions.  Since 1970 excess water pumped from the mine as part of the dewatering programme of the mine was disposed of at two locations on the farm Fritz 540 and to the west of the N-S striking diabase dyke forming the western boundary of the southern compartment, as well as to the north of the mine. Some 11 Mm3 was used for irrigation on the farm Fritz at Onverwagt during the period 1978 to 1983 while the rest was disposed of onto the open field through a system of canals and pipelines. Some of it has also been disposed of directly into the Gamagara River near the farm Lanham, but the amount and duration of this practice is still uncertain. As this practice could have constituted a form of artificial recharge of the alluvial aquifer associated with the Gamagara River, a final answer to the questions of volume disposed and duration of disposal is required before a conclusion can be made whether the groundwater resource on the farms Fritz 540, Lanham 539, Bishops Wood 476

Mine name Report Summary of the conclusions of the report and possibly also Wright 538 benefited from this practice.  An analysis of historical (1966 to 2002) groundwater levels in boreholes in and close to the Gamagara River illustrate that the impact of dewatering at the mine is restricted to the Southern groundwater Compartment and that the N-S dyke forms the western boundary of the dewatering zone. Depending on the depth of weathering of the N-S diabase dyke forming the western boundary of the Southern Compartment, and the water level in the alluvial aquifer downstream of the dyke, groundwater from the downstream alluvial aquifer can decant into the dewatered Southern Compartment. The downstream distance over which this process will have a negative impact on water levels in the alluvial aquifer has been calculated and is not expected to exceed about 3 km. Downstream of the farm Parson; the available data indicate that fluctuations in groundwater levels in the lower Gamagara River did not exceed 15 m since 1966.  From the observed response in groundwater levels after large flood events such as occurred for example in 1988, it is concluded that the amount of water that infiltrated to the depth of the water level in the dewatered compartment at that time and recharging the deep primary aquifer below the riverbed across the dewatered Southern Compartment amounted to about 5% of the flood volume. Where the dewatering has no impact on ground water levels, for example downstream of N-S diabase dyke, a similar flood would have a much larger positive impact on the groundwater levels in the alluvium of the riverbed. Downstream of the N-S diabase dyke, however, flood events of long duration do have a positive impact on the groundwater levels in the alluvium of the riverbed.  Preliminary groundwater recharge calculations based on annual recharge figures provided in a recent study by VSA Geoconsultants (2006), some 60 000 m3 could have been contributed annually to the alluvial aquifer from the Kalahari sediments that have now been removed by the mining activity. These are however preliminary figures and further studies on this aspect are required.  For smaller floods, such as the one in February 2006, approximately 20% of the flood volume infiltrates into the upper few metres of the alluvium in the riverbed. The rest was captured in the sink and other geological structures along the route.  The N-S fault and associated brecciated quartzite zone visible along the eastern edge of the erosion feature at the old golf course acted as a major conduit for water infiltration as early as the 1988 and 1991 flood events. Based on the simulated flood volumes and calculation of flow rates at specific points in the river, it is estimated that some 3 x 106 m3 of water infiltrated along the fault zone during the February 2006 flood event.  Based on the historical flow record, the simulations of river flow by Chapman (2006) and the effect of the dewatering had on the natural infiltration mechanisms, it is concluded that a flood event of at least 15 x 106 m3 at the confluence on the farm Demaneng 546 is required to cause substantial flow in the downstream sections of the Gamagara River at the farm Wright 538 and further downstream under the current dewatering conditions and consequences thereof.  After the 1988 flood only the flood event of 1991 had the size that resulted in the flood to reach Debeng.

Mine name Report Summary of the conclusions of the report During the later period (1991 to 2006) there was not only a lack of flood events, and thus limited groundwater recharge, but the disposal of mine water to the lower sections of the Gamagara River was also discontinued, thereby removing the source of water for artificial recharge. Both these factors are believed to have contributed to the decline in groundwater levels in the alluvial aquifer.  Despite the sink at the old golf course capturing a proportion of large flood events, there has also been a lack of the type of rainfall events over the past 15 years that would have resulted in large enough flows to replenish the alluvial aquifer along the lower reaches of the Gamagara River. Meyer [15]. Development of a Meyer [15] formulated a conceptual geohydrological conceptual geohydrological model of the mining area and the immediate surrounding model, an evaluation of the areas. The intended use of the conceptual model was to effect of dewatering and the define the extent of the area impacted by the design of a monitoring groundwater dewatering so that the mine can operate at protocol, Sishen Iron ore Mine the current depths of open case mining. The conceptual model addressed the following questions:

 What are the horizontal and vertical limits of the SIOM dewatering?  How much water is being recharged to ground water?

The area has undergone numerous tectonic events resulting in numerous faults, dyke intrusions, thrust faults and doming and the associated folding and turning of strata [15]. These structural elements control the movement of both surface water and groundwater. Meyer [15] made the following conclusions about the Gamagara River:

 The nature of the primary Gamagara aquifer is dependent on the directly underlying rock formations. The Gamagara River is believed to follow distinct structural directions, notably NNW and E-W. In the upper reaches the river traverses mainly dolomitic rocks and along directions that have been subject to extensive and deep erosion and dissolution of dolomite over a long geological time period and subsequent backfilling with breccias and conglomerates of various kinds. Lower down the river traverses a mainly quartzitic and lava basement more resistant to erosion and resulting in a relatively shallow river channel.  In the upper reaches the hydraulic connection between the Gamagara aquifer and the secondary dolomitic aquifer is in general better than where the aquifer is underlain by lava and quartzite.  During large flood periods in the Gamagara River, the alluvial deposits in the river valley are fully recharged. Also during such periods it is believed that the recharge from the water saturated alluvium in the river channel to the underlying dolomitic aquifer is more significant than the recharge to the lava and quartzite formations underlying the lower reaches of the river channel.  As a result of the surface flow in the Gamagara River being captured in recent years mainly by the large N-S structural feature that crosses the river near the old golf club, surface flow in the downstream sections of the Gamagara River has virtually ceased. This has had a major negative impact on the amount of ground water recharge to the downstream Gamagara aquifer, resulting in water level declines in boreholes tapping this aquifer. The boreholes tapping this aquifer are relatively shallow with the results that a water level

Mine name Report Summary of the conclusions of the report decline of a few metres can cause the drying up of an otherwise sustainable borehole.

Due to the multiple tectonic events and dyke intrusion exploiting different structural directions, the dykes are believed to be fractured along intersections allowing movement of ground water across dyke structures in these areas [15]. Despite the fracturing affecting the hydraulic characteristic of the dykes, and thereby allowing the movement of ground water across dykes, sections of the dykes are still believed to act as barriers to ground water flow [15]. It was concluded by Meyer [15] that most of the dykes, although retarding ground water flow, are not totally impermeable and effectively forming total barriers to ground water flow in the region.

During early-Karoo times (~300 Ma) a NW directed glacial channel was eroded into the older basement and filled in with tillite and shales of the Dwyka Group [15]. These deposits extend from just east of Kathu in a northwesterly direction and reach thicknesses of more than 200 m on the farms Woon 469 and Curtis 470 but do not outcrop [15]. The southern boundary is along a line from just south of Kathu towards the Gamagara River in the west, while the western boundary is a line roughly along the Gamagara River in a NW direction [15]. The northern boundary is not well defined at this stage but appears to be along a line just north of Kathu, across the farms Kathu 465 and the southern part of Marsh 462 [15]. This low permeability formation effectively forms a barrier to ground water movement to a depth of approximately 200 m [15]. There is however a concern that the Dwyka barrier may not act as efficiently in future if the planned deeper level mining, and hence the further lowering of the water levels below the ore body, are implemented [15].

An analysis of available information by Meyer [15] allowed defining the current boundaries of impact on ground water levels to be as follows:

 The eastern boundary is defined as the Sekgama dyke.  The southern boundary is currently conveniently taken to be the E-W dyke across the farms Kadgame 558, Mokaning 560 and Jenkins 562. Some monitoring boreholes on the farms King 561, Mokaning 560 and Mashwening 557 to the north of the dyke show drawdown values around 80 m, while others are significantly less. Current thinking is that those boreholes showing large drawdown are located along prominent N-S structures (faults or dykes) that are directly and hydraulically connected to the main dewatering boreholes in the mine. The effect of the dewatering in this area is not well understood yet and more intensive monitoring on either side of the dyke is recommended.  The impact to the north is currently restricted by the presence of the Kalahari and Dwyka Groups and extends to approximately the middle of the farm Sacha 468 boundary. Golder [19] have postulated this boundary to be a NE-SW directed dyke, but no evidence for the presence of such a dyke could be found. If there is indeed a dyke present in this position, it is not expected to penetrate the Dwyka and Kalahari. As current potentiometric levels are still well within the Kalahari and Dwyka formations, a dyke forming a ground water flow boundary is ruled out.  The western boundary is roughly along the centre of the farms Woon and Fritz and extends southwards

Mine name Report Summary of the conclusions of the report to the intersection with the Gamagara River. Golder [19] have also identified a N-S dyke to form the northern part of the western boundary, but no evidence for the presence of a dyke structure could be identified. There is some evidence that the triangular shaped area north of the Gamagara River excluded by Golder [19] as part of the dewatered area, may well be affected by dewatering, but additional monitoring positions are required in this area to resolve the issue. South of the Gamagara River the western impact boundary is along a prominent N-S dyke that can be followed for a long distance on the aeromagnetic map.

By using geological cross sections, together with water level cross sections, the role of geological formations and dyke intrusions in defining the edge of the dewatering impact zone was made easier [15]. Where previous studies emphasized the role of dykes acting as physical flow boundaries, this results from this study could not confirm these that the dykes play as significant a role are previously stated [15]. The Gamagara River aquifer upstream of the farm Parsons is regarded as a separate aquifer system not directly connected to the deeper hard rock aquifers [15]. Although water levels may still fluctuate, this is believed to be the result of normal; seasonal and climatological cycles [15]. Water level monitoring records kept by individual farmers for the last approximately 15 months and submitted to Sishen Iron Ore Mine do not indicate any significant variations and definitely no continuous downward trend is recognizable [15]. Allegations of possible impact by the Sishen Iron Ore Mine dewatering on the farms Rissik 330 and Ettrick 378, more than 40 km north and northeast of SIOM, was ruled out [15]. Meyer farm investigations Investigations were done by Sishen Iron Ore Mine on a number of farms based on concerns by landowners that the dewatering activities have influenced the boreholes on their properties.

 Sishen Iron Ore Mine responded to complaints about groundwater level declines on the farm Crossley 660. An report was issued by Meyer [37] in 2009 by revised by the author in 2010 based on comments received from the landowner concerned [38]. Meyer [38] concluded that the water levels measured are currently in the same range as before the 1973/74 high rainfall period and before large scale ground water abstraction occurred at Sishen Iron Ore Mine. It was decided that the ground water resources on the farm Crossley 660 have not been in the past and are not currently impacted by the large scale ground water abstraction performed by Sishen Iron Ore Mine.  The owner of the farm Wormald 482 near Dibeng addressed three important questions to Sishen Iron Ore Mine regarding the geohydrological conditions on his farm and possible hydraulic connections between potential aquifers on his farm and the dewatering operations at Sishen Iron Ore Mine. These three questions raised were: (a) What is the general water level in the primary aquifer in the vicinity of the farm? (b) Is the primary aquifer at Wormald connected to the dewatered areas? (iii) Is the secondary aquifer (at Wormald) connected to the Sishen Iron Ore Mine and how can it be determined? o Approximately 30m to 40m of mostly unconsolidated Kalahari Group sediments representing mainly the upper Gordonia Formation of the Kalahari Group, overlie lava and quartzites of the Ongeluk and Lucknow

Mine name Report Summary of the conclusions of the report Formations respectively. o It is unlikely that any of the lower sections of the Kalahari Group (Eden, Wessels and Budin Formations) or sediments representing the Dwyka Group, are present. o Some NE-SW directed linear structures of pre- Dwyka age, interpreted from aerial surveys, are present on the farm. An unnamed non-perennial stream on the farm may have exploited the structurally weak zone formed by one of these structures in the underlying rock formations. o If the sediments of the Kalahari Group are partially or totally saturated with groundwater, these saturated sediments would constitute a primary aquifer. o The underlying hard rock formations (lava and quartzite of the Ongeluk and Lucknow Formations) have virtually no primary porosity in which groundwater can be stored or released from. When weathered, fractured, jointed or faulted, secondary porosity is created in these rocks and when saturated with groundwater, will represent a secondary aquifer. o Because the static groundwater level was found to be usually below the base of the Kalahari Group succession, these sediments do not represent a primary aquifer. Following exceptionally high rainfall periods associated with high rainfall recharge to the aquifers, groundwater levels may rise into and saturate the lower layers of the Kalahari Group thereby forming a relatively thin and unsustainable or temporary primary aquifer. It was concluded that in the vicinity of the farm Wormald, the Kalahari Group sediments do not represent a primary aquifer as the static groundwater level is mostly below the base of these sediments. The answer to Question (a) above is therefore that as no primary aquifer exists at Wormald, there cannot be a static water level in the this aquifer. As a result of this conclusion, any reference to a hydraulic link or connection between a primary (potential) aquifer and the dewatered areas as a result of the dewatering activities at Sishen Iron Ore Mine is thus inappropriate. The answer to Question (b) above is therefore “No”. o The underlying rocks of the Lucknow and Ongeluk Formations in the region form a secondary aquifer. No confining layer is present in or below the base of the Kalahari Group to describe the underlying secondary aquifer as a confined aquifer. o Current groundwater levels are similar to those originally recorded when boreholes were drilled, although fluctuations have been recorded following exceptionally high rainfall periods. o A number of geological and geohydrological conditions are described that could allow a hydraulic connection between the secondary aquifer at Wormald and that present at the mine. It is concluded that although a hydraulic connection cannot be ruled out totally, and taking into consideration different geohydrological conditions, it is unlikely that water levels in the secondary aquifer at Wormald will be affected by the dewatering at SIOM. There is currently no evidence that groundwater flow occurs from Wormald towards the mine as a result of the dewatering actions at Sishen Iron Ore Mine.  Sishen Iron Ore Mine investigated complaints by the

Mine name Report Summary of the conclusions of the report farmer regarding the groundwater conditions on the farm Beaumont 569. Meyer [39] found that the current water level situation is similar to that before the heavy rains in 1974/76 and it was concluded that the current water levels are equal to close to the static ground water level in the area. Furthermore, the current depth to the groundwater level on the farm Beaumont is between 34 m and 40 m below ground level which was significantly deeper than is generally found in boreholes further to the west and which are drilled into lava of the Ongeluk Formation. Meyer [39] determined that the much deeper water levels on Beaumont are because all boreholes on this farm are drilled into quartzites of the Lucknow Formation where different geohydrological conditions exist. Based on the above it was concluded that the large scale abstraction of groundwater at the Sishen Iron Ore Mine has had no negative effect on the ground water resources on the farm Beaumont 569.  A complaint was received about boreholes on the farm Brooks 568. From the analysis of all available information Meyer [40] concluded that the water levels measured currently in boreholes on the farm Brooks represent a situation where levels have returned to the natural long term static water level condition.  Meyer [41] investigated whether mining operations at Sishen Iron Ore Mine could in any way be responsible for the apparent declining borehole yields on the farm Dundrum 475. According to Meyer [41] the groundwater level measurements in the area between the farm and the mine indicate a relatively steep groundwater gradient directed towards the farm. At the groundwater divide southeast of the farm the ground water level is more than 65 m above those measured in boreholes on the farm Dundrum. This induced ground water flow in the direction of the farm implies that it is very unlikely that the dewatering operations at the mine will have resulted in declining ground water levels on the farm Dundrum 475 [41]. There is also no evidence for the presence of geological structures, such as faults and dykes that could act as preferential pathways or conduits for ground water movement between dewatered areas and the farm [41]. Follow studies by Meyer [42] conducted on the farm included a series of test to assess the productivity of specific existing boreholes and to determine the cause of the alleged decline in borehole yield. The collapse of boreholes has reduced the water inflow area significantly, and together with carbonate incrustation, is believed to be the main causes of declining borehole yields. In some of the boreholes incorrect borehole construction prevented optimal abstraction.  In response to claims that water levels are declining on the farm Gappepin Reserve 670 due to mine dewatering Meyer [43] conducted field investigations. Meyer [43] concluded that the majority of the boreholes and wells on the western side on the farm Gappepin Reserve 670 are in general not being affected by the large scale ground water abstraction. Two of the boreholes towards the southern portion of the farm (boreholes GP-05 and GP-06), anomalously deeper ground water levels have been observed. At borehole GP-05 the water level is currently some 25 m deeper than in other boreholes. Apart from the deeper water levels a more important concern is that the water level in borehole GP-05 has declined by 22 m between 2001

Mine name Report Summary of the conclusions of the report when it was constructed and 2010 - a rate of more than 2 m per year. Based on a 1979 water level recorded in the NGDB for borehole GP-06, the water level in this borehole dropped by 26 m over a period of 21 years. These rates of decline are significantly faster than the long term slow decline observed in the other boreholes in the region [43]. It was concluded that the decline of water levels observed in boreholes GP-05 and GP-06 has to be attributed to dewatering operations at Sishen Iron Ore Mine [43]. As follow-up two new monitoring boreholes were drilled by Sishen Iron Ore Mine as part of their regional monitoring borehole network and to investigate the hydraulic properties of an east-west directed structural lineament between the two boreholes seen on satellite imagery [44]. Pumping tests were conducted on the two boreholes as well as a series of geophysical investigations in selected areas across observed structural lineaments. Observations of water levels in all boreholes along this lineament have not showed any substantial change over the past year to support the earlier conclusion that these boreholes may be impacted negatively by Sishen Iron Ore Mine dewatering. Furthermore, the water level in borehole GP-05 is now back where it was in 2001 when the borehole was drilled.  A complaint describing declining groundwater levels and reduced inflow into boreholes and wells on the farm Langlaagte, a Portion of Gamaliets 659 was submitted to Sishen Iron Ore Mine by the landowner [45]. Based on an analysis of the information, Meyer [45] concluded that: (a) pre-1974 ground water levels are similar to those that are currently experienced in the region; (b) the excessive rains over the 1974/76 rainfall periods cause a significant groundwater recharge event, which resulted in rising groundwater levels over large areas in the Kathu district; (c) over the period 1976 to about 2000 natural decline in water levels occurred towards the long term static groundwater levels experienced before 1974; (d) since about the year 2000 groundwater levels have remained reasonably steady and appear to fluctuate within the range of natural long term fluctuations; (e) no evidence was found that the alleged decline in groundwater levels and diminishing inflow into boreholes at Langlaagte during the period 1997 to around 2000 and later, are related to or as a result of the dewatering activities practiced by Sishen Iron Ore Mine in order to mine safely and efficiently.  Sishen Iron Ore Mine received a request from the owner of the eastern portion of the farm Murray 570 to investigate the declining groundwater levels on the farm [46]. Meyer [46] concluded that the current water levels measured in boreholes on the farm Murray, as well as on many other farms in the region that are outside of the defined influence of the dewatering activities of Sishen Iron Ore Mine, are believed to represent a situation where levels have returned to a level resembling the natural long term static groundwater level condition.  Sishen Iron Ore Mine received a request from the owner of the farm Tamplin 477 to investigate alleged declining groundwater levels on the farm. As part of the investigation, the geohydrological conditions on the neighbouring farm Kameel 570, which also belongs to same landowner were also investigated and assessed [47]. Meyer [47] formulated a conceptual geohydrological model for the area to explain the observed geohydrological

Mine name Report Summary of the conclusions of the report conditions; identified different aquifers in the region; and explained the current groundwater level situation in view of the alleged declining water levels experienced over the last six years. o The upper layer is formed by geological sequences representing different formations of the Kalahari Group, notably the upper unconsolidated sands (Gordonia formation), followed by calcrete (the Mokalanen formation), and in places a layer consisting of poorly sorted gravel or pebbles with clay (interpreted as representing the Budin formation) is present at the base of the Kalahari Group. These formations attain thicknesses varying between approximately 40m and 60m across the farms Tamplin and Kameel. These formations are deposited on an erosional surface of the much older Ongeluk lava formation. The underlying lava formation is expected to be at least 200m thick in the area. The upper part of the lava may be weathered but little evidence is available to support this statement. Drilling to depths of 200m has shown that the lava is massive and contains very few groundwater yielding fractures. The lava has no primary porosity and any groundwater intersected occurs in fractures caused by secondary geological processes. This model differs from the one developed in 2009 for the area immediately surrounding the Sishen Iron Ore Mine in the sense that geological structures, such as faults and dykes are apparently absent in the area with the result that ground water movement is not controlled by such structures. o Indications are that the sediments of the Kalahari Group, despite expected to have a relatively high primary porosity and relatively high hydraulic conductivity, do not in general host a reliable groundwater resource to form a high yielding and sustainable primary aquifer. Although the current groundwater levels and thickness of Kalahari Group deposits on the farm Tamplin appear to be such that 5m to 10m of water saturated sediments are present forming a low yielding primary aquifer, the hydraulic characteristics of this aquifer are such that it does not support high yielding boreholes. As a result the Kalahari sediments are not regarded as representing an aquifer of large significance in this region. The observation that almost all boreholes on the farm Kameel are drilled to depths of more than 100m is interpreted as indicating that the overlying Kalahari Group sediments do not contain or cannot yield sufficient groundwater to warrant the installation of large pumping equipment. Boreholes are therefore drilled much deeper in the hope to intersect higher yielding fractures in the lava. Therefore the underlying lava formation, when suitably fractured, is considered to be the more important and reliable aquifer for the region. o By using the limited information of groundwater level response with time, it was concluded that current ground water levels as measured on the farms Tamplin and Kameel are at levels and elevations roughly similar or even higher than the water levels recorded earlier. If it is indeed true that water levels have been declining over the last number of years, this has been due to natural causes and not as a result of any actions

Mine name Report Summary of the conclusions of the report related to the groundwater abstraction actions at Sishen Iron Ore Mine.  A letter describing declining groundwater levels and reduced inflow into boreholes on the farm Smythe 566 (Remainder), was submitted to Sishen Iron Ore Mine by the landowner [48]. Based on investigations Meyer [48] concluded the following: o Pre-1974 ground water levels were similar to those that are currently experienced in the region. o The excessive rainfall over the 1974/76 and 1988/91 rainfall periods resulted in significant groundwater recharge. The first recharge event resulted in an apparent 10m, and possibly even more, rise in borehole water levels. The 1988/91 rainfall period resulted in another recharge event during which water levels, based on the water level response recorded in boreholes on other farms in the Kathu region, probably increased again by a few metres. o As a result of the combined effect of these recharge events, borehole water levels remained above the long term static water level for an extended period. At the farm Smythe 566 this period extended apparently to the mid- 1990s and on some other farms in the region possibly even longer. o Following on the 1974/76 recharge period, a natural water level decline started in about 1977 and continued until about 1988. Between 1988 and 1991 another smaller recharge event again resulted in water level rise of a few metres, whereafter the natural rate of decline continued towards the long term static groundwater levels experienced before 1974. This decline in groundwater levels is a natural process and is attributed to natural drainage losses during periods of no or low groundwater recharge. o From the available information it appears as if the long term static water level could have been reached around the mid- to late-1990s in boreholes on the farm Smythe. The water level information recorded for boreholes on the farm Smythe 566 since 2001 indicate that groundwater levels have remained reasonably steady from 2001 onwards and appears to have remained within the range of expected natural long term fluctuations. o It can be expected that groundwater recharge did occurred over the last about 10 years when the annual rainfall often exceeded the long term annual average of about 330mm. However, it would appear that this rainfall was not sufficient to result in substantial groundwater recharge similar to that experienced during the two periods described in this report. o No evidence was found that the alleged decline in groundwater levels and diminishing borehole yields at boreholes on the farm Smythe 566 Remainder, are related to or as a result of the dewatering activities practiced by Sishen Iron Ore Mine as part of the mining operations.  The farm Vlakwater, the south-western portion of the farm Jenkins 562, was visited to investigate complaints that groundwater levels in boreholes on the farm were declining and there was insufficient water to supply in the stock watering needs [49]. In this case, the main problem is believed to be that the boreholes are too shallow to accommodate natural and seasonal fluctuations in the groundwater level. In the interim it is recommended that the boreholes

Mine name Report Summary of the conclusions of the report which previously had a sufficient and sustainable yield should be deepened to the original depths [49].  Meyer [50] reviewed available water level information for boreholes on the farm Curtis 470. Based on a review of this information the following conclusions were made:  The long-term ground water level records as measured in the two deep boreholes CS01 and CS02 on the farm Curtis 470, which represent the conditions in the deep aquifer below the Kalahari Group geological succession, indicate that the deep aquifer at both these two boreholes was being impacted by recent increased mine dewatering activities associated with the northward expansion of mining activities. This conclusion confirms the observation reported in October 2013 at the meeting with the farming community that the impacted area is believed to be expanding towards the farm Curtis and needs to be monitored closely. o The shallow aquifer associated with the calcrete succession of the Kalahari Group in this area is, however not impacted on the farm Curtis 470. This aquifer is largely protected from mine dewatering impacts by the presence of the thick impermeable clay layer underlying the calcrete. Water level records representing both the shallow and deep aquifer from adjoining farms to the south, are in agreement with the above conclusions. This finding was also made by Meyer [51].  A complaint was received by Sishen Iron Ore Mine from the owner of the farm Spence 537 that the water yield from this borehole has lately declined [52]. The conclusions reached by Meyer [52] were as follows: o The currently installed Grundfos SP 1A-21 submersible pump driven by a 0.55kW 3- phase electric motor is the same that was installed in the borehole at the time of the initial pumping tests in April 2007. According to the manufacturer's specification the maximum yield of this pump is 0.4l/s. During the pumping tests in February 2015 the yield delivered by this pump as measured at the borehole was 0.4l/s which agrees with manufacture's specifications, and is similar to the yield of 0.38l/s recorded during the pumping tests in April 2007. o The yield delivered to the storage tanks on Spence was measured on 27 February 2015 as 0.25l/s. According to the performance curves for this pump, the yield should be about 0.3l/s when taking into account the additional head of approximately 53m between the borehole and the storage tanks. The difference of 0.05l/s between the predicted and measured yield at Spence can probably be attributed to friction losses along the approximately 10km 50mm diameter pipeline between the borehole and the tanks. o It is concluded that there has been no change in the yield of the pump since 2007 and the pump is currently performing according to specifications. o Based on the interpretation of the 2015 pumping test results the current recommended long-term sustainable yield of the borehole has been calculated to be 1.0l/s. This calculated yield is dependent on the static water level which in turn determines the available drawdown and therefore it is critical that the static water level of the borehole is monitored regularly.

Mine name Report Summary of the conclusions of the report o The main fracture supplying water to the borehole is at a depth of approximately 17m below ground level. This level is referred to as the critical water level depth that should not be exceeded during pumping. By pumping at a rate of not more than the recommended sustainable yield of 1l/s and for a continuous period of not more than 8 hours, the water level will not exceed this critical level. o The 1.08 m decline in the static water level since 2007 has had no negative impact on the ability of the currently installed pumping equipment to deliver the same yield at Spence as before. The allegation in the complaint letter that the water delivery at Spence is significantly lower than before due to a lowering in the ground water levels, is therefore incorrect. Groundwater Consulting GCS [86] compiled a hydrogeological database using Services investigations data from all users in the D41J catchment. Data was received from Sishen Iron Ore Mine, other consultant companies, farmers and public domain databases [86].

GCS [12] was appointed by Sishen Iron Ore Mine to conduct a study of the Gamagara River Aquifer from the Farm Demaneng 546 in the South to Dagbreek 474 in the North. The following conclusions were made, amongst others [12]:

 Mining activities in the catchment has reduced the runoff by 3%;  Mining dewatering has increased the depth to the groundwater table within the dewatering zone;  Transmission losses are as a result of the effects of the mining dewatering activities in the dewatering zone, as well as due to the swallets.  The increased storage capacity in the River channel sediment causes more water from floods to be diverted into the aquifer. This is especially true for smaller floods which take longer to cross the dewatered section.  It seems that an average seepage rate for the Riverbed of around 1x10-5 m/s could be assumed for the section of the River crossing the dewatering compartment.  Subsidence features (swallets) further increase the transmission losses along the River and most flood events are likely to be captured in the swallets. Therefore flood and river flow recharge event downstream of the dewatered zone is likely to be affected.  The availability of flow data to calibrate any model is a major shortcoming to ensure accurate results. Monitored measuring weirs up- and downstream of the dewatering compartment would have assisted in this regard.  A correlation between rainfall depth and flood volume was found, however, more records for flood events of over 50 million m3 are needed.  Due to the absence of major rainfall events in recent times and the absence of corresponding flow data in the River, it is not possible to state whether recent rainfall events caused, or should have caused flooding in the River or not, compared to historical floods in the Gamagara River.  Mining had not had a significant impact on the groundwater flow in the early 1970’s.  The groundwater levels emulated the topography in 1963 – 1973 in the area of the current dewatered zone. The groundwater levels in the Gamagara River alluvial aquifer were relatively shallow and

Mine name Report Summary of the conclusions of the report likely to be un-impacted during 1963 to 1973. The Gamagara River was most likely a gaining stream pre 1973 along the entire extent between Demaneng and Dagbreek.  The groundwater gradient is towards the Gamagara River on both the south western and north eastern side of the River (outside the dewatered zone). At the time of the investigation the, Gamagara River is a gaining River outside the dewatered zone. Inside the dewatered zone (Moria to Demaneng); the Gamagara River is a losing stream.  The 1974 flood/rainfall recharged the Gamagara River aquifer significantly resulting in a ~2-10 m increase in groundwater level (~1-3 m per year). The 1988 and 1991 flood rainfall events also contributed significantly to the recharge and consequent increase in groundwater levels of the Gamagara River aquifer. Water levels increased also by between 2-10 m downstream of the period 1991 and 1997 the rate of decline increased to ~0.6 m per year. To the eastern and north eastern side of the mine, the boreholes showed a rate of decline of ~0.8m between 1974 and 1988, the rate increased to 0.9m per year between 1991 and 1999. From 2000 onwards (to 2004) the rate of decline decreased to ~0.2 to ~0.6 m due to higher rainfall over this period. It is therefore likely that regional groundwater level in the area does show a natural decline after each major recharge event.  The rate of decline in some of the boreholes found in the dewatered zone range from 2 to 14 m per year. The average groundwater level decline between recharge periods is ~5 m per year in the dewatered zone. Therefore the rate of decline of selected boreholes inside the dewatered zone is higher than those outside the dewatered zone (as can be expected).  Two recharge mechanisms of the Gamagara River alluvial aquifer can be deduced, viz. recharge from surrounding aquifers (currently only outside the dewatered zone) and recharge from flow/flood events in the Gamagara River. Recharge from the surrounding aquifer outside the dewatered zone is likely to be minor. Major recharge of the Gamagara River alluvial aquifer is dominated by flow events in the River. It is likely that if no flow events are found in the Gamagara River then the water level in the Gamagara River alluvial aquifer will be similar (or in equilibrium) to the surrounding fractured and karst rock aquifers. Flood events in the stream channels resulted in deep infiltration and ground water recharge of the alluvial aquifers.  Should flow/flood events occur in the Gamagara River, larger flow losses are likely to occur especially between Demaneng and Moria, not only due to the effects of dewatering, but also due to the swallets structure near the western dewatered boundary.  Therefore the dewatered zone and associated swallets has impacted on recharge to the Gamagara alluvial aquifer downstream of the farm Moria.  No evidence of artificial recharge to the Gamagara River aquifer can be deduced from the data. However, it appears as if artificial recharge does occur near the north part of the eastern slimes dams.  No significant difference in geochemical signatures can be seen in the boreholes associated with the Gamagara River aquifer and those in the Kalahari sediments and fractured rock aquifers except on farms such as Bishopswood and Rozenvlei. It can be deduced that any surface water discharge

Mine name Report Summary of the conclusions of the report emanating from the mine is unlikely to have impacted negatively on the Gamagara River aquifer at the time of the investigation.  In view of the above, the Gamagara River aquifer does appear to be impacted by dewatering practices at Sishen Iron Ore Mine between Demaneng and Dagbreek.  Furthermore, the impact is likely to be permanent. As this study did not extend further downstream of Dagbreek, no comment can be made on the status of the aquifer downstream of Dagbreek. The farm Dagbreek is located near the D41J catchment boundary, therefore monitoring of boreholes downstream of this farm along the Gamagara River should occur (in the D41K catchment).

A groundwater monitoring system was developed by GCS [36] to determine the impact of the Sishen Iron Ore Mine dewatering on the surrounding aquifer and groundwater users. A total of 94 boreholes were proposed as part of the monitoring system.

GCS [58] identified and assessed if the available and existing numerical models can be used to serve as a regional groundwater model of the D41J catchment. The ability models to predict the impact of the Sishen dewatering operations on the surrounding groundwater users were also evaluated. The models evaluated were [58]:

 Clean Stream Groundwater Services (Pty) Ltd, 2009, Numerical groundwater model in aid of dewatering design for Sishen Mine, January 2009. The main aim of this model was to estimate the required dewatering rates at which SIOM must dewater to ensure dry mining conditions.  Meyer R., 2009, Final Report on development of a conceptual geohydrological model, an evaluation of the effect of dewatering and the design of a monitoring protocol, Sishen Mine, Rep # 009/09, June 2009. Reinie Meyer’s conceptual groundwater model for the area. Please note that this is not a numerical model;  Goussard, F., 2011, Table 10. Tentative Outline of Report on Dewatering at Sishen, Atkinson numerical model. This model is designed is to assist the mine with its dewatering strategy, however it was not yet completed at the time of the investigation; and  Clean Stream Groundwater Services (Pty) Ltd, 2004 Geohydrological inputs to fulfil the EMP requirements for the Bruce-King-Mokaning iron ore project of Associated Manganese, Ref BKM01/2004. This numerical groundwater model was done for the Khumani Mine. However, this model has however not been updated for a number of years.

GCS concluded that no model appears suitable to act as a regional (catchment scale) model. Therefore a new model should be developed which can be used as an impact management tool. The conceptual model developed by Meyer [15] and GPT15 should form the basis of the regional numerical model of the D41J catchment, should it be developed. AGES investigations AGES was appointed by Sishen Iron Ore Mine to conduct a groundwater specialist study in support of the Environmental Management Programme (EMPR) component of the mining right application [16]. The

15 Geo Pollution Technologies -Gauteng (Pty) Ltd (GPT), 2010, Evaluation Of The Hydrogeological Data at Khumani Mine and the Development of a Groundwater Management Plan, GPT Reference Number: Kum-09- 403, Assmang Ltd Khumani Iron Ore

Mine name Report Summary of the conclusions of the report proposed development would consist of open pit mines, mechanically placed overburden residue facilities and haul roads. The groundwater impacts from new developments were postulated as follows [16]:

 The Vliegveld West Pit would be the first new operation to mine through the present western compartment boundary dyke in 2020. The potential impact was delineated based on the location of dykes. It is known that the existing compartment boundaries are formed by dykes and that dewatering takes place within compartments.  There are two scenarios interpreted for the potential groundwater impact zones: (a) The first scenario is that the dewatering would reach the next significant north-south trending fault zone to the west, which is currently inferred to act as a groundwater flow boundary, based on water level differences to the east and west of this structure. This compartment can be termed the “Parsons Compartment” and the zone of influence is expected to impact on the north-western half of Parsons and the north-eastern corner of Dingle. The significance of this boundary is as yet uncertain and will have to be confirmed with geohydrological investigations. (b) The second scenario is a more conservative approach was followed by assuming that only known dykes would form the compartment boundary. This compartment can be termed the “Dingle Compartment”. This zone is expected to impact on the western half of Parsons, the eastern half of Dingle, the northwestern part of Roscoe, the eastern half of Smythe and the northeastern part of Bredenkamp.  Potential contamination from the overburden and waste rock dumps could be from nitrate that is derived from the blasting process. Mine Water Consultants MWC [31] conducted a critical review of previous studies investigation at Sishen Iron Ore Mine. MWC fully agreed with the extent of the Meyer [15] dewatering cone as portrayed in his conceptual model report. A slightly larger area in the northwestern corner of the dewatering cone is the only difference in the MWC [31] interpretation compared to Meyer [15] dewatering cone. There were concerns about dewatering taking place along the Dwyka Glacial Valley resulting in lowering the groundwater yields for some of the farms. This was shown to be unlikely as flow is away from the mine this implicates that dewatering along the paleo-channel does not occur; no reverse gradient exists [31]. MWC [31] agreed with reports that due to the absence of major rainfall events in recent times and the absence of corresponding flow data in the river, it is not possible to state whether recent rainfall events caused, or should have caused flooding in the river or not, compared to historical floods in the Gamagara River. They found with available data, it is impossible to pin liability to the mine or anyone else for the decrease in aquifer yields on the farms to the west of the Gamagara River.