COARSE SAND RESOURCES OF THE BRISBANE REGION

by A W Stephens Extractive Industry Unit Department of Mines and Energy

EIU Report No.2 October, 1997 2 CONTENTS SUMMARY ...... 4 INTRODUCTION ...... 6 Aims and Scope ...... 6 Acknowledgments ...... 8 Terminology and Use of Coarse Sand ...... 9 Origin ofNatural Coarse Sand Deposits ...... 11 Special Characteristics of Coarse Sand Resources ...... 13 CURRENT OPERATIONS AND PRODUCTION ...... 14 Brisbane River Tidal Reaches ...... 14 History ...... 14 Present ...... 17 Brisbane River Catchment Upstream Channels and Alluvial Terraces ...... 18 Priors Pocket to Wivenhoe ...... 18 Wivenhoe Upstream ...... 20 Buaraba Creek...... 21 Lockyer Creek...... 22 Pine River ...... 22 Coomera River ...... 24 Logan River ...... 25 Mary River ...... 25 Other Sources ...... 25 Manufactured Sand ...... 25 FUTURE DEMAND ...... 27 Controls on Coarse Sand Demand ...... 27 Demand Estimates for Total Sand & Gravel ...... 27 Demand Estimates for Coarse Sand ...... 28 Future Demand Estimates ...... 28 FUTURE RESOURCES ...... 29 Remaining Resources of the Brisbane River Tidal Reaches ...... 29 Modern Rates ofBrisbane River Sand Supply ...... 30 Brisbane River Catchment Upstream Channels and Alluvial Flats ...... 31 Priors Pocket to Wivenhoe ...... 31 Wivenhoe Upstream ...... 33 Buaraba Creek...... 34 Cress brook Creek ...... 35 Pine River ...... 35 Coomera River ...... 35 Mary River ...... 36 Other Sources ...... 36 Manufactured Sand ...... 3 6 CAPACITY OF KNOWN RESOURCES TO SUPPLY THE SHORTFALL ...... 40 Boral's Own Capacity to Make Up the Boral "Case 2" Shortfall ...... 40 Other Operators' Capacity to Make Up the Boral "Base Case" Shortfall ...... 41 Expected Longer Term Increases in Demand ...... 4 5 RESOURCE PLANNING ...... 47 CONCLUSIONS ...... 49 REFERENCES ...... 52 3 List of Figures

Figure 1. Graph of sand and gravel production from the Brisbane River tidal channel ... 17

Figure 2. Locations of coarse sand operations and resources, Brisbane Region ...... end of report

Figure 3. Locations of coarse sand operations and resources, Buaraba Creek ...... end of report

Figure 4. Locations of coarse sand operations, Pine Rivers ...... end of report

List of Tables

Table 1. Annual production of sand and gravel from the Brisbane River tidal channel ... 16

Table 2. Coarse sand production and additional supply capacity, Brisbane region 1997 ...... 43

Table 3. Natural coarse sand resources, Brisbane region ...... 46

List of Appendices

Appendix A Coarse sand resources information proforma ...... end of report 4

SUMMARY Pioneer Concrete (Qld) Pty Ltd officially ceased operations on the tidal reaches of the Brisbane River in April 1997. Bora! Ltd will cease in the next few years or sooner, depending on the outcome ofseveral studies.

Natural coarse sand is produced from small-scale operations in stream beds, to large­ scale off-stream operations by major vertically integrated companies. The major operations are in the tidal in-stream and non-tidal off-stream deposits of the Brisbane River, Coomera River and Pine River. The ongoing dredging of the Brisbane River from the early 1980s to the present has been essential not as a source of gravel, but for the continued supply ofthe coarse sandfractionfor pre-mixed concrete.

Demand for coarse sand is controlled by population growth and the state of the construction industry which has been cyclical, especially the demand for concrete. From a variety ofdata the following demands for coarse sand are estimated: Economic upcycle (1990-95) 3. 6 Mtlyr Economic downcycle (1995-97) 2. 6 Mtlyr

Alternative sources of coarse sand within economic transport distances of Brisbane are limited. Existing sources of similar natural sand, chiefly the Pine Rivers, Coomera River, upper Mary River and non-tidal reaches and alluvial flats ofthe Brisbane River near Ipswich are themselves limited and are already committed. To be available for the period 1997- 2000, any individual coarse sand resource has to have all land and access controls and operational approvals in place now to be relevant to the issue of determining whether alternatives are available to the tidal reaches ofthe Brisbane River.

Manufactured sand from hardrock quarries has recently begun to replace some of the natural sand in concrete. Pioneer, Hymix, Excel, Bora!, CSR and Nucrush already use manufactured sand in concrete plants. Some operators are producing true "manufactured sand", and others are basically using treated crusher dust blended with natural coarse sand. Manufactured sand has specific requirements for particle shape and particle size distribution, which can be partly controlled by crushing and screening technology.

However, not all rock types have the mineralogy and petrology to allow the production of the required cubical particles, no matter what crusher technology is used. Additionally, for particle shape reasons, there will be an increased demand for fine natural sand when manufactured sand becomes commonplace. Concrete finishing, water bleeding and shrinkage have been problems with manufactured sand elsewhere. At present, the production rate of manufactured sand is also controlled by the ability to sell the co­ produced coarse aggregate, otherwise large areas would be needed for stockpiling. However, at Wolffdene Quarry the coarse aggregate can be kept in the crushing cycle to tailor all production to meet sales demand.

Because of the variety of Bora/'s rock types, it will take some time to complete research on the balances between particle size distribution versus shape and texture, cement paste and 5 water demand to produce economically viable manufactured sands. Bora! will also need time to research crushing and screening/classifying technologies applicable to their various rock types.

If Bora! 's application to continue dredging the river is refused there will be an immediate decrease in the supply of coarse sand. However, about 480 000 tlyr of coarse sand could be supplied by operators other than Bora! to supply the shortfall from 1997 to 1999. This analysis is based on the difference between current production rates and current maximum production capacity, and assumes no capital investment in plant by the other operators as such costs might increase the price to consumers. If upper Mary River operations are limited by riverine management concerns, the additional supply capacity might reduce to 415 000 t/yr.

Should Bora! 's Brisbane River application be refused, the major potential suppliers of additional sand would be CSR, East Coast Gravels, Neilsens Quality Gravels, Excel, Pioneer, Nucrush and to a lesser extent small operators in the upper Brisbane River. However, a major company such as Bora! may not wish to buy from a smaller competitor in the concrete market and thus assist their growth. Transport of manufactured sand from Glasshouse (Excel), and natural sand from Buaraba Creek (Nucrush), and the upper Brisbane River might increase the final costs due to the extra transport distance.

Resource depletion impacts on Bora! itself would be present but have not been casted. However, the resource depletion impacts on other companies, such as East Coast Gravels, Neilsens, Pioneer (Bald Hills), and perhaps CSR might be to use up their resources earlier than planned, but in time scales longer than the 1997-1999 period.

The above interpretations apply to the current economic downcycle conditions only. Forecasts of population growth and a predicted return to economic growth in the construction industries suggests that the demand for coarse sand resources will increase substantially in the next couple of decades. This analysis suggests that 4. 5 Mtlyr of coarse sand might be required by 2001, 5.0-5. 7 Mtlyr by 2011, and 5.8-6.9 Mtlyr by 2021. The present supply is 2. 6 Mtlyr and the present capacity is about 3. 0 Mtlyr.

It is clear that known resources of natural coarse sand will not be adequate for continued future supply. Although use of off-stream resources might alleviate some environmental pressures, there is virtually no regional-scale information on off-stream resources for southeast Queensland.

Increasing use of manufactured sand will transfer the planning problems from natural sand and gravel onto hardrock and fine sand resources. However, even the current bank of approved hardrock resources will be exhausted within 20 to 30 years, although the life of individual resources will vary greatly, and further resources may be approved in the future. However, unless further natural sand resources can be approved or there is a dramatic incre·ase in manufactured sand production, there may be a significant shortfall in coarse sand supply by 2001, which will be unrelated to Bora! 's tidal reaches operations. Any removal ofBora! from the tidal reaches will exacerbate the situation. 6 INTRODUCTION

Extractive resources (natural sand & gravel and crushed rock aggregates) are fundamental to our man-made environment, and represent a large proportion of the materials used in constructions of all kinds. Queensland's production of extractive raw materials is valued at about $250 million per year, and is our fourth highest value mined product (after coal, copper and gold). However, value-adding of the raw materials in local construction produces enormous economic benefit for the community.

The local extractive industry underpins regional development, maintaining employment and providing a wide range of infrastructure. Extractive resources, either as road pavement materials or in concrete products, are used in all construction of : • schools, hospitals, and other public utilities; • factories and other commercial buildings; • residential housing; and • construction and maintenance of roads and rail lines.

None of this construction can be accomplished without these basic raw materials.

Deposits of natural sand and gravel suitable for producing construction materials are limited in occurrence and must meet specific economic criteria, such as quantity and quality of sand, thickness and nature of overburden, proximity to consumers, and be economical to transport. Furthermore, viable resources must be capable of being worked in accordance with government conditions and regulations, and extractive operations must be compatible with surrounding land uses and not cause significant or unmanageable environmental harm.

Aims and Scope The end of 135 years of extraction of sand and gravel from the Brisbane River entered the first phase on 16 April 1997 when Pioneer Concrete (Qld) Pty Ltd officially ceased operations on the tidal reaches (O'Flynn, 1997). Dredging by the one remaining operator, Boral Ltd will cease in the next few years or sooner, depending on the outcome of studies including an Environmental Impact Study being carried out by the company in support of an application for a phased withdrawal over the next three to four years.

If Boral's application to continue dredging in the river is refused there will be an immediate decrease in the production of coarse sand. The Policy Council of the Brisbane River Management Group (BRMG) wish to receive proof from the extractive industry that there is no alternative viable source of coarse sand other than the tidal reaches of the Brisbane River, with the qualification that the source is "readily available". The ability of various other operations to supply this shortfall is assessed in this report. 7 However, the assessment necessarily involves some assumptions. Given sufficient financial incentive and sufficient lead time to gear up with new plant and staff, some individual operators could supply the entire annual demand of southeast Queensland at least for a short time. This is the nature of commerce. However, this could not be achieved immediately with the current plant at maximum capacity, and would rapidly deplete the operator's resources, thus transferring the problem to adjacent areas or into the future.

Therefore, the assessment of what additional coarse sand other operators could supply assumes that current operations are not upgraded through capital investment in plant, since these costs might be passed on to the consumer via increased prices. The estimate of additional supply capability is simply assessed as the difference between "current maximum production capacity" and current production rates. However, the maximum production capacity is really only notional, since in the competitive world of extractive industry, operators are constantly varying plant and configurations depending on contracts and prices. Production is also constrained by operational conditions limiting hours of work and truck travel etc.

This report provides information on the remaining resources of coarse sand in the Brisbane region that could act as alternative supplies to the coarse sand presently extracted from the tidal reaches of the Brisbane River. The report documents current coarse sand extraction operations, and provides an inventory of potential coarse sand resources and the obvious constraints on their future utilisation. Additionally, the status of manufactured sand is examined as an alternative to natural sand for the period November 1997 to December 2001.

No formal cost- benefit analysis or impact assessment of the (already approved) alternatives has been attempted.

The administrative regime for extractive industry in Queensland results in private companies needing to allow for a lead time of 5-l 0 years to secure all approvals to begin production. Therefore, from a practical point of view, resources available for extraction in the period November 1997 to December 2001 must already have all access/ ownership and approvals requirements in place now. Resources without such approvals in place are included in this report only for completeness, but should not be a factor for decision making, because in practice they would not be available for extraction. 8

Acknowledgments The compilation of this report was assisted by a Coarse Sand Working Group made up of industry and government representatives as follows:

Convenor: Andy Stephens, Extractive Industry Unit, Department of Mines and Energy

Industry: Lionel Armitstead, Boral Construction Materials Qld Rowland Bendall, CSR Readymix Pty Ltd Dugald Gray, Nucrush Pty Ltd John Johnson, Excel Concrete Pty Ltd Peter Martin, Pioneer Concrete (Qld) Pty Ltd

Local Councils: Barry Ball, Brisbane City Council Maurie W ann, Esk Shire Council

State Departments: Lloyd Andersen, Department of Transport Jeff Clark, Coastal Management Branch, Department of Environment Peter Curley, Planning and Assessment Section, Department of Environment Jim Dale, Department ofNatural Resources Dan Johnson, Department of Main Roads Greg Oliver, Brisbane River Management Group, Department of Environment Mike Patchett Department of Environment

The contributions of the Working Group members are gratefully acknowledged. The above industry representatives rapidly returned questionnaires, readily participated in personal and telephone interviews providing some previously confidential information, and corrected and added to the draft report. Other members of the Working Group provided useful additional information and constructive criticism.

Gordon Williams (Hymix), Chris McGirl (East Coast Gravels), David Kershaw (resource consultant), John Siemon (resource consultant), and Kyle Waye (Department of Natural Resources) also provided information and expert opinion.

Peter Hoffenberg (Department of Local Government and Planning) provided the digital streams base for Figures 2, 3 and 4 at short notice. 9

Terminology and Use of Coarse Sand In geological terminology 'sand' is specified world-wide as having particle-size ranges below 2 mm down to 0.0625 mm. 'Gravel' has particle-size ranges above 2 mm to less than 60 mm. Geologically, 'coarse sand' particles are larger than 0.5 mm, while 'medium and fine sand' particles are smaller than 0.5 mm. There are other grainsize class boundary points for 'very coarse sand', 'medium sand', 'very fine sand' etc.

This report uses industry terminology as in Australian Standard AS 2758 rather than the geological terminology. The major industry terms are 'coarse aggregate' and 'fine aggregate'. Coarse aggregate refers to natural or crushed stone with particle sizes above 5 mm diameter, while fine aggregate is less than 5 mm diameter.

Fine aggregate comprises 'coarse sand' and 'fine sand'. Coarse sand is finer than 5 mm diameter, with less than 10% finer than 0.015 mm. The boundary with fine sand is not formally specified by AS 2758, but fine sand is generally less than 1 mm particle diameter.

In the Brisbane region, coarse sand is mainly used for pre-mixed concrete and concrete products. Concrete products include masonry blocks, concrete roof tiles, and concrete pipes and poles. Other uses include mortar sand, plaster sand, bedding sand, asphalt sand, filtration sand, architectural finishes, brick texture surfacing, and a wide variety of miscellaneous industrial uses.

The Australian Standard for pre-mixed concrete is quite wide with respect to particle size distribution (AS 2758.1 - 1985: Aggregate and Rock for Engineering Purposes. Part 1: Concrete Aggregates- Standards Association of Australia). However, individual construction contracts may require much tighter specifications, for example, Queensland Transport's Standard Specification Roads - MRS 11.70 for concrete in roads and bridges, wherein the fine and coarse aggregate components must conform to AS 2758.1.

Concrete products also generally require sand that complies with AS 2758. The preferred sand is medium to coarse grained with some fines below 0.15 mm diameter to fill voids, and rounded particle shape for lower abrasion on moulds.

Concrete roof tiles and masonry blocks require small percentages of particle sizes from 1.4 mm to 2.4 mm for strength, and waterproof tiles further require particle sizes from 0.15 to 0.3 mm for filling voids (Pecover, 1986).

Mortar sand should also comply with AS 2758, and a component of silt size particles can be tolerated and enhances workability.

Sand for cement and gypsum plaster should comply with AS CA27 -1959 (Pecover, 1986), and generally consists of 0.3 to 2 mm particle sizes. 10

Bedding sand and gravel for bedding and supporting pipes and cables should be porous, free from clay, silt, and organic matter and should pack densely.

Asphalt sand for road surfacing and bituminous weather proofing requires coarse angular grains with little fines or silt. For Queensland Transport Standard Specification Roads MRS 11.09, the fine aggregate component refers to particle sizes smaller than 2.36 mm.

Queensland Department of Transport specifications for the Pacific Highway upgrade require 50% of the fine aggregate in the concrete pavement to be natural sand, with at least 75% quartz. This requirement is already raising concerns within the extractive industry regarding the ability of companies to supply to specification. 'The Government is saying it wants natural sand, not manufactured sand' (D. Gray, Nucrush, pers. comm. 1997).

Whitehouse and others (1996) provides information on typical usage rates of sand and other rock materials:

To make 1 km of 4 lane motorway requires: Concrete pavement - 3 240 t sand, 7 800 t coarse aggregate, and 1 620 t cement. Asphalt pavement - 540 t sand, 2 400 t fine aggregate, 3 600 t coarse aggregate, 8 400 t roadbase, and 300 t bitumen.

An average brick veneer house on a concrete slab with tiled roof requires: Concrete- 13.6 t construction (coarse) sand, 17.9 t coarse aggregate, 5.9 t cement; Mortar- 12 t mortar sand, 2 t cement, and 1.5 t lime; Bricks - 40 t clay or shale; Tiles - 10 t clay; and additional rock and sand for fill, landscaping, driveways etc.

Typical large city office building: 19 000 t sand and 27 000 t coarse aggregate.

'",..ill Rjfif UfFt ._11 f I 1 . ?_"1~·------~--~ 11

Origin of Natural Coarse Sand Deposits Coarse sand deposits occur as: a) modem in-stream channel deposits - active bed load in river beds, in dynamic equilibrium with modem flood processes and climatic and environmental conditions; b) fossil off-stream channel deposits - former bed load deposits either in older alluvial terraces or underlying modem floodplains, and unrelated to modem conditions; c) estuarine channel deposits - either modem or fossil deposits being reworked by modem tidal currents and flood flows in the lower estuarine reaches of present streams (in-stream).

Modem in-stream channel deposits comprise sand and gravel deposited during floods in stream beds of present watercourses. Channel deposits are generally free of excessive silt and clay. Mining may be simple, consisting of dredging or excavating, followed by washing and screening to obtain aggregate in marketable size gradations. These deposits are generally desirable for aggregate due to abrasion having left only hard, strong, sub-rounded particles, which are desirable for concrete.

In some places the river is incised within higher older terraces forming high banks rarely overtopped by modem floods. Here the modem floodplain equivalent cannot form a wide spreading plain. Instead narrow benches form within the high banks at the modem floodplain level. This is the case in the upper Brisbane River, where the term 'floodplain' can be used for these narrow 'in-stream' benches because of its useful genetic connotations.

Fossil off-stream channel deposits generally comprise a veneer of fine sand, silt and clay deposited during ancient floods or even major modem floods by periodic channel overflow onto plains that border the stream channels. The fine grained veneer may overlie older sections of coarse sand and gravel deposits produced by past meandering of the stream channel. Fine sand, silt and clay pockets infilling old abandoned channels may be contained within the coarse grained former channel deposits.

Alluvial terraces comprise higher, older, bench-like off-stream deposits that were produced by floods during previous climatic/environmental cycles or events. They are not in any dynamic equilibrium with the modem flood levels or sea levels. Because they are significantly older than the modem deposits they generally have well developed soils produced through prolonged weathering.

In geologically young terrains, which are generally mountainous and steep, modem channel and bench deposits are replenished by seasonal floods. However, in older geological terrains with more subdued topography, the rate of active supply of new sand to the river channels may be very low. Even where large resources of sand and gravel occur in river valleys, the modem supply rate may be low. Such deposits may have formed over several hundred 12 thousand years in response to past sea level and climatic cycles of the Pleistocene epoch. This is the case in the Brisbane River valley and estuary.

The catchment geology has a strong effect on the size and competency of the sand particles produced. Streams draining older Palaeozoic tectonic blocks such as the D' Aguilar, Beenleigh and Y arraman blocks can provide coarse sand and gravel from a variety of metamorphosed volcanic and sedimentary rocks which include granitic inliers in places. This is the case for the Coomera, middle Brisbane, and Pine Rivers. Streams draining essentially unmetamorphosed Palaeozoic blocks can also provide coarse sand and gravel from volcanic and granitic rocks, for example, Buaraba and Cressbrook Creeks. The upper Brisbane River drains volcanic rocks of the early Mesozoic Esk Trough, which provide immature gravel and coarse sand. Streams draining Mesozoic blocks such as the Ipswich and Clarence-Moreton basins can provide only fine-medium sand from the sandstones and mudstones. This is the case for the Albert-Logan, Oxley, Bremer, and Lockyer systems.

Marine tidal delta sands in northern Moreton Bay and the smaller tidal inlets of the open coast have been derived from the marine quartzose sand province of the Australian east coast (Stephens, 1992). This suite has been through numerous sea level transgressions and regressions, and can only provide fine sand of very uniform particle size (poorly graded).

Off-stream resources are more expensive to work because of the added costs associated with exploration, overburden removal, washing and rehabilitation, in addition to land purchase costs or royalty payments to the property owners (DPI, 1995b ). These extra costs could result in an increase of about $7.50/t on the Sunshine Coast (DPI, 1995b).

Some effects of in-stream extraction are not apparent for many years due to the inherent time lag in the natural system (DPI, 1995b ). Bed and bank erosion are the most obvious potential impacts, although bed and bank erosion occurs naturally in many streams. Bed degradation is the extensive and progressive lowering of a river bed over time due to the sediment transport rate exceeding the rate of sediment supply (Erskine, 1990). This is distinct from scour which is localised and temporary. In areas where the banks are sandy and erodible, such deficits in the sediment budget can also be made up by bank erosion rather than bed degradation.

In-stream estuary channel dredging also has environmental consequences. Dredging of the Brisbane River for aggregates has been criticised on environmental grounds for decades. Adverse impacts have been re-suspension of mud, locally adding to water turbidity; noise nuisance for riverfront residents, although this has been managed in recent years; and visual amenity impacts depending on the attitude of the viewer. At the same time, extraction under water and barging of the product by river has had some significant environmental benefits (O'Flynn, 1997). Heavy truck transport has been unnecessary and other impacts such as noise and dust and energy use have been less than might have been experienced had the aggregate been supplied from hardrock quarries.

''"""'..... ~x.o~ ..~ ... ,.."'.-.--llll~-·~--aze-·.,.., _...,.... ___ _._._o ___ llt~W·-·-· ------13 Special Characteristics of Coarse Sand Resources Construction materials are essential community resources. Access to economic deposits of coarse sand for construction is a prerequisite for the continuing existence of an urbanised society. However, in growing regions the very process of urbanisation itself tends to restrict and limit the availability of these natural resources, forming reliance on more distant and hence more costly deposits.

Nowhere are the socially and environmentally adverse effects of 'mining' more apparent than in urban areas. Planners and environmentalists have responded by restrictive legislation and zoning regulations. These avoid local conflicts (not-in-my-backyard), but seriously jeopardise long term supply if no other resources have been properly protected.

There is generally a lack of demand forecasting, resource assessment and resource protection. Hence, local constraints applied without considering the regional implications, end up producing new conflicts for future generations.

Coarse sand resources are not re-useable. They have a long service life in construction, and hence new supplies are required for each generation. Coarse sand resources are extremely limited in their degree of recycling. Re-use of concrete is an insignificant proportion of total demand and is likely to remain so for the foreseeable future, especially in areas of high population growth such as southeast Queensland.

Coarse sand resources are non-renewable. Although coarse sand deposits in some central and northern Queensland streams are actively regenerated with fresh supplies from the hinterland, this does not occur to any significant degree in southeast Queensland. The majority of in-stream deposits in southeast Queensland are replaced during floods by upstream bed remobilisation, but extraction of this sand produces a deficit in the downstream section where the bed has also been remobilised. Such situations should be thought of as essentially non-renewable resources like their off-stream counterparts and like hard rock resources. If such deposits are needed for construction, their extraction requires careful consideration of potential effects on the hydrodynamic stability of modem environments, because they will not actually be replenished by natural processes, despite anecdotal information to the contrary.

Coarse sand resources are uncommon. The location of coarse sand deposits is fixed by geological events of the past. Not all sediment deposits are suitable for extractive industry use or for economic extraction, processing and transport. It takes an uncommon combination of geological events to produce an economically viable extractive resource.

Allowing extraction of resources that are close to users has both economic benefits through lower transport costs, and environmental benefits through less truck traffic and lower transport infrastructure needs. Like transport infrastructure, extractive industry resources may be seriously limited if long term planning horizons are not catered for. 14 Coarse sand resources are where they are, and not where we would like them to be. It is not possible to site extractive industry workings according to ideal planning models in the same way that residential, commercial, educational and industrial centres can often be located to achieve desired physical and social interactions.

A valuable coarse sand resource is where it is; its location is non-negotiable. A clear grasp of this intractable truism by the planning profession and environmental and community action groups is necessary before due weight is given to the need for proper planning measures for extractive resources. However, without a basic understanding of the science of geology, it is difficult for most people to grasp this important concept.

CURRENT OPERATIONS AND PRODUCTION Natural coarse sand is produced from a variety of situations in southeast Queensland, from small-scale intermittent one-man operations in the beds of active streams, to large-scale off-stream operations by major vertically integrated companies. The major operations are in the tidal in-stream and non-tidal off-stream deposits of the Brisbane River, Coomera River and Pine River.

Coarse sand is almost always associated geologically with gravels. Depending on the type of deposit, materials are worked by barge-mounted clam-shell dredges, excavators, draglines, endloaders and suction dredges. Untreated sand dug from the active bed of river channels or from beneath alluvial flats does not always conform to the standard specifications for various construction uses. This can be due to inappropriate distribution of particle sizes, presence of clay, silt, gravel, charcoal, or due to weak particles, grain coatings, or alkali reactivity. Therefore processing can add significant value to the raw product, as does its use in the final products of construction.

Although production of manufactured gravels (coarse aggregate) by crushing hard quarryrock has been ongoing since the 1970s to augment natural river gravels, the manufacture of coarse sand sized aggregate from hardrock is very new on a world scale. ·

Note: Where data on coarse sand and gravel volumes have been obtained from published reports and converted to tonnes, a conversion factor of I m3 = I. 5 t has been applied in this report.

Brisbane River Tidal Reaches

History Aggregates won from the river have undeniably provided a major contribution to the commercial and residential construction in the City of Brisbane. Until the late 1970s, the river provided the only source of aggregate for concrete and other construction uses for Pioneer, although Readymix had an alternative source of aggregate in the Ashgrove 15 Quarry. In the last two decades, however, the proportion of gravel in the dredged material has steadily declined to about 20 percent of the product, and has been augmented/replaced by crushed stone aggregate.

Total reserves of sand and gravel originally in the tidal reaches were estimated at over 100 million tonnes (Malempre, 1989), and about 40 Mt has been extracted (Malempre, 1990, O'Flynn, 1997).

Decreasing gravel yield and increased demand for materials led to the establishment of hardrock quarries around the periphery of the city for the supply of crushed coarse aggregate. However, these quarries were unable to supply the coarse sand component of Brisbane River aggregate so necessary in concrete to ensure a well-graded mix producing the desired strength at minimum cost. The only alternative natural sources of this sand fraction, the Coomera and Pine Rivers and their alluvium, were also being heavily exploited during this period and becoming depleted. Consequently the ongoing dredging of the Brisbane River from the early 1980s to the present has been essential not as a source of gravel, but for the continued supply of the coarse sand fraction.

However, dredging the river for aggregates has been criticised on environmental grounds. At the same time, extraction under water and barging of the product by river has had some significant environmental benefits (O'Flynn, 1997). Heavy truck transport has been unnecessary and other impacts such as noise and dust and energy use have been less than might have been experienced had the aggregate been supplied from hardrock quarries. Adverse impacts have been re-suspension of mud, locally adding to water turbidity; some noise nuisance for riverfront residents, although this has been managed in recent years; and visual amenity impacts depending on the attitude of the viewer.

Boral Resources (Qld) Pty Ltd, Pioneer Concrete (Qld) Ltd and their subsidiary companies comprising the Brisbane Sand and Gravel Producers Association formerly held permits approved by Cabinet and issued under the Harbours Act by the Department of Transport as the delegate of the Treasurer to dredge gravel and sand from the bed of the Brisbane River. These are now administered by the Department of Environment.

Dredging by Association members was confined to that section of the river between Kinellan Point at New Farm and Venus Pool at Karana Downs, although there were a number of closed sections within that length.

In 1983-84, Tepara Pty Ltd, then a subsidiary of Denison Resources, was granted permission to extract fine aggregate from the lower reaches from Norris Point at New Farm (just downstream of Kinellan Point) to Ovens Head, St Lucia, to a maximum of 70 000 m3/yr (105 000 t/yr). Coarse aggregate was to be screened and returned to the river. Monarch Sands Pty Ltd later held and operated this permit, but were bought by Boral in August 1995. The dredging locations for each company were allocated on a rotational 16 basis at meetings of the Association. By 1989 there were thirteen barges and one trailer­ suction dredge in operation.

Although dredging continues in the lower estuary ofthe river, production has declined markedly since the peak production of 1 450 000 m3 in 1976-77.

Table 1. Annual Production of Sand and Gravel from the Brisbane River Tidal Channel.

Year Production Production m3 tonnes 1976/77 1 450 000 2 175 000 1977/78 1 150 000 1 725 000 1978/79 750 000 1 125 000 1979/80 900 000 1 350 000 1980/81 730 000 1 095 000 1981/82 682 000 1 023 000 1982/83 789 000 1 183 500 1983/84 774 729 1 162 094 1984/85 851 093 1 276 640 1985/86 845 466 1 268 199 1986/87 787 238 1 180 857 1987/88 947 788 1 421 682 1988/89 806 634 1209951 1989/90 743 697 1115 546 1990/91 647 548 971 322 1991192 estimated 600 000 900 000 1992/93 530 000 795 000 1993/94 540 000 810 000 1994/95 440 000 660 000 1995/96 380 000 570 000

Source: Figures supplied by the former Department of Harbours and Marine and Department of Transport. Note: Post 1990/91 data from Department of Environment.

Annual production figures for the period 1976-77 to 1995-96 are listed in Table 1, based on statistics supplied by the former Department of Harbours and Marine, the Department of Transport, and the Department of Environment. Dredging production reached a peak of 2 175 000 t/yr (1 450 000 m3/yr) in the mid 1970s, declined to 1 125 000 t/yr in 1978-79, remained more or less static until 1988-89 and subsequently declined to a 15-year low of 570 000 t/yr by 1995-96 (Fig. 1).

lf 17

Brisbane River Tidal Channel Sand Dredging

2500000

2000000

E c: 1500000 0 ..u ;;, '0 ..0 1000000 Q.

500000

0 1'- IX) m 0 ..... N C") '

Figure 1. Graph of sand and gravel production from the Brisbane River tidal channel.

The proportion of gravel won has been steadily decreasing for some years as the deposits with higher gravel content were worked preferentially. Most aggregate won during this period came from between the Centenary Bridge and the Central Business District (CBD) reaches of Brisbane City (O'Flynn, 1992).

Separate figures for sand and gravel components produced are not available. However, the companies indicate that this would now consist of 80% fine aggregate and 20% coarse aggregate. Since the optimal ratio for concrete is between 5.5-6.0 'coarse aggregate' : 4.5- 4.0 'fine aggregate', the dredged material must be supplemented with crushed rock from hardrock quarries if an acceptable concrete blend is to be produced.

Present Pioneer Concrete (Qld) Pty Ltd ceased operations in the tidal reaches on 16 April 1997 (O'Flynn, 1997).

Boral Resources (Qld) Pty Ltd currently dredges sections of the Brisbane River between Goodna and New Farm, with production between 350 000 and 450 000 t/yr of sand and gravel (80% is coarse sand). Product is processed at two plants - 17 Mile Rocks (Jindalee ), and Goodna. Winning of the material by Boral is by barge-mounted clam-shell dredges Lucinda and Jindalee of up to 1000 t capacity, which are propelled by push tugs to the riverside processing plants, and the 3000 t capacity self-propelled Darra.

At the 17 Mile Rocks and Goodna plants the raw feed is washed to remove clay, silt and organics, and classified into various sizes, usually 20 mm, 10 mm, 5 mm, coarse-medium 18 sand, and oversize which is recycled and crushed to the finer sizes. The wash water is returned directly to the river without settling out of the mud component.

Brisbane River Catchment Upstream Channels and Alluvial Terraces In addition to the tidal reaches dredging operations, several companies win sand and gravel from the upstream river bed, side bars, point bars and some terraces remote from the channel using endloaders, draglines, and excavators. These sites are mostly upstream of the tidal areas, with the in-stream operations administered by the Department of Natural Resources under the Water Resources Act, and off-stream operations administered by the relevant Local Authority under the Local Government (Planning and Environment) Act.

In upstream areas production has been significantly boosted by a large operation on the alluvial terraces at Priors Pocket, and by operations at point and side bars adjacent to the channel, such as Colleges Crossing previously and other areas farther upstream at present.

The proportion of gravel in these 'dry' deposits is generally higher than in the dredged material, commonly up to 50% coarse aggregate (O'Flynn, 1992). However, some deposits contain a relatively large proportion of oversize cobbles and boulders which must be either crushed or rejected. Aggregates from these sources are generally more expensive to produce because of trucking costs to crushing and screening facilities, and often require more washing because of a higher silt and clay content in the raw feed. With the depletion of gravel in the channel downstream, such 'dry' deposits in upstream areas could become increasingly important, particularly for the western part of the Brisbane-Ipswich market (O'Flynn, 1992).

Priors Pocket to Wivenhoe The Department of Primary Industries carried out a resource planning study (DPI, 1995c) of sand and gravel resources for the Brisbane River between Colleges Crossing and Wivenhoe Dam for the Brisbane River Management Group. This information has been augmented from company data for the present study.

Priors Pocket Pit: With BCC approval in 1987 for "Particular Development - Extractive Industry and Filling", Boral Resources (Qld) Pty Ltd opened the large Priors Pocket Pit in 1988 on the low terrace forming the western section of this large fossil point bar (Fig. 2). The sand and gravel horizon is about 10 m thick lying mainly beneath the water table beneath about 6 m of overburden of silty clay (O'Flynn, 1992).

The project so far has involved the development of large on-stream lakes at either end of the deposit, initially excavated by bulldozer above the water table but later by barge­ mounted clam-shell dredges. Overburden is removed by scrapers and dozers, and stored for rehabilitation works.

·~~tl'* ~1-illli ltit!l ~,t.ill ~~ 1 - 1"ill' WM_ll -~~ fi¥....._,_,______' 19 The sand and gravel is transported by barge and processed at the company's nearby Goodna and 17 Mile Rocks plants by washing, screening, classifying, and crushing of oversize material. Production is presently about 300 000 t/yr, comprising 210 000 t/yr of fine aggregate (coarse sand) and 90 000 t/yr of coarse aggregate (gravel) (L. Armitstead, Boral, pers. comm., 1997). These products supply Brisbane markets south of the Brisbane River and west to Ipswich, and are used for ready-mixed concrete and concrete products.

Boral anticipate completion of production in 1999.

Colleges Crossing Pit: Pioneer Concrete (Qld) opened the large Colleges Crossing Pit in early 1988 in a side bar deposit upstream ofthe Mount Crosby Road crossing. Product was trucked to the company's plant at Seventeen Mile Rocks. The deposit was estimated to contain 1 Mt prior to extraction and was worked out by late 1991. The site was progressively re-contoured and re-vegetated while extraction was proceeding, and was rehabilitated as a large lake and recreational area.

Kholo Pit: CSR Readymix extract about 3 000 m3/month of loam from a site upstream of the Kholo road bridge (Fig. 2), but have applied for a large on-stream lake operation for coarse sand.

Sapling Pocket/ Summerville Pits: The CSR Readymix Group works the Sapling Pocket Pit on a point bar on the southern side of the river that is worked by excavator at water level.

The CSR Readymix Group also works the large Summerville Pit, which is up to 20m deep on private property on the upper terrace west of Sapling Pocket and a scraping in an abandoned channel. The terrace deposit is worked under a Ipswich City Council permit, while the channel deposit is worked under a Controlled Quarry Material (CQM) permit managed by the Department of Natural Resources. The Summerville Pit is accessed via a haul road through the Sapling Pocket deposit which fords the river. In the large terrace pit, poorly sorted gravel and sand up to 9.2 m deep occurring under 1 to 4m of silty overburden is worked by endloader. Material is trucked to the company's processing plant at Tivoli via Pine Mountain Road.

Total production from the two sites (Sapling Pocket and Summerville) has been about 250 000 to 350 000 t/yr of sand and gravel, with about 200 000 to 300 000 t/yr of coarse sand (R. Bendall, CSR, pers. comm., 1997). The company's original plan for the site and ultimate end use were to extract to 5 m below water level leaving an on-stream lake. DNR has refused this proposal, and all extraction will be above water level.

Andrews (Fernvale) Pit: R V Andrews & Sons Pty Ltd have worked a point bar deposit about 1 to 2 km upstream of Burtons Bridge, Fernvale for almost 20 years under a CQM permit. Screening and concrete hatching facilities are located nearby. Only small quantities of sand and gravel are produced to supply local concrete plants. 20

Schmidts Pit: Diggers Landscape Supplies re-opened the former Boral Resources Schmidts (or Femvale) Pit in 1994 under a QM permit held by the landowner G. Jensen 3 (DPI, 1995c) and produced about 22 000 t (15 000 m ) in the first year. Available resources at the site are likely to be small due to DNR constraints to prevent flood damage.

Wivenhoe Upstream The Department of Natural Resources has recently carried out an inventory of coarse sand and gravel operations in the Upper Brisbane River between Monsildale Creek and the headwaters of Lake Wivenhoe (Waye, 1997). This report updates the previous report by DPI (1995b).

Numerous past operations, generally at either small production rates or as once-off extractions are described by Waye ( 1997), from which the following information has been obtained.

3 DNR statistics show that about 0.75 Mt (0.5 Mm ) of sand and gravel have been extracted from the Upper Brisbane River over the past 10 years (Waye, 1997). DPI (1995b) reported 1994 production of sand and gravel of 150 000 t from the upper Brisbane River and 30 000 t from Buaraba Creek. The largest operations have been at Campbell's Pit (AMTD 270), MRD pit at AMTD 262, and several pits between AMTD 254 and 247 (Mount Williams meander). At present, production rates are low, and dominated by Wilson's Moorabool operation (AMTD 248).

[Note: AMTD =Adopted Middle Thread Distance in kilometres from the river mouth.]

No wholly off-stream operations are current, but two large off-stream operations are proposed near Toogoolawah (Strathdee and Wirralee).

Management plans for riverine quarry material being prepared by the Department of Natural Resources are likely to restrict any increases in production rates, and may result in a marked decrease in production from in-stream deposits in the non-tidal reaches of the Brisbane River.

Operations that take trivial quantities of coarse sand and gravel intermittently or that have been suspended in recent years are located at Brisbane River (Oupan), Brisbane River (Redlins), Brisbane River (Andrews), and Brisbane River (Esk S. C.) (Fig. 2).

Moorabool Pit (AMTD 248-246): The Moorabool Pit, off Gregors Creek Road, 1s operated by Hitec Resources (Wilson and Jackson). This is currently the largest operation upstream of Lake Wivenhoe at about 18 000 t/yr, with over 150 000 t of coarse sand, gravel, and fine-medium sand being extracted since 1993. 21 Staghurst Pit (AMTD 250): Neil Hughes, the most recent operator of the Staghurst Pit, has extracted 45 000 t of coarse sand and gravel since 1993. A significant proportion of the material is oversize gravel (DPI, 1995b ). Product is trucked to the Sunshine Coast via Kilcoy.

Gregors Creek Bridge (AMTD 252-251): Hitec Resources extracted about 38 000 t of coarse sand and gravel from two sites downstream of the bridge in 1994-95. Esk Shire Council takes small amounts immediately downstream of the bridge. Lowood Sand and Gravel (Hertrick Bulk Haulage) has taken over 9 000 t from the low floodplain since 1994.

Sinnamon Lane (AMTD 254): Karreman Brothers Pty Ltd extracted 30 000 t of coarse sand and gravel in 1995. Production was reduced in 1996, but has recently increased. A modern and well planned screening plant with substantial tailings ponds and upgraded highway access has been constructed by Karreman so that processing is completely off­ stream beyond the high terrace. Product is trucked as far as Brisbane City.

Cambrook Pit (AMTD 262): The Department of Main Roads has recently ceased operations on a large point bar deposit adjacent to Cambrook Station off Cambrook Road. Since 1992 about 150 000 t of gravel has been extracted for the D' Aguilar and Brisbane Valley Highway upgrades.

Campbell's Pit (AMTD 270): A pit downstream of Allerys Bridge near Moore has been worked on a small scale for many years by Gaults Sand and Gravel. Leighton Contractors Pty Ltd took 129 000 t of coarse sand and gravel in 1995 for the Wivenhoe-Tarong Pipeline project. The Department of Main Roads and Esk Shire have taken minor quantities over many years upstream of Allerys Bridge.

Linville (Williams) (AMTD 280): Messrs Williams and Draper take small quantities for local markets. Large resources of sandy gravel are present.

Buaraba Creek DPI (1995b) reported on current operations in the Buaraba Creek area.

Buaraba (Nucrush): Nucrush operating as Brisbane Valley Sand & Gravel, operate a large off-stream pit under Esk Shire Council consent 1 km downstream of Skew Gully on Portion 79, which is owned by Independent Turf Supplies (ITS).

Overburden is removed by end loader and dump truck. Product is extracted by front end loader above water level and by dragline below water level. Wet screening uses a hindered settling classifier and hydrocyclone to process the coarse sand. Truck & dog and semi­ tippers transport the product via the Gatton-Esk Road to the Warrego Highway, and thence west to Toowoomba and east to Brisbane and the Gold Coast. 22 This pit has been operating since 1991, but production figures were not available to DPI (1995b ). Total production is 60 000 to 120 000 t/yr, comprising 30 000 to 80 000 t/yr coarse sand (D. Gray, Nucrush, pers. comm., 1997).

Buaraba (ITS): ITS operates a large pit immediately upstream of the Buaraba (Nucrush) pit on Portion 79, and eventually plan to create an on-stream lake integrated with the Nucrush pit (DPI, 1995b ). ITS holds a CQM permit as well as an Esk Shire Council permit.

Fine sand to fine gravel, landscaping boulders, and potting mix are produced and marketed in Brisbane and the Gold Coast. The operation began as in-stream dredging in mid 1993 3 producing about 8 250 t (5 500 m ) in 1993-94.

Other: Other small operators in Buaraba creek are Buaraba (Zanow), Buaraba (Beaumont), and Buaraba (Brooks) (Fig. 2). Applications are in progress at Running Creek, Buaraba Lot 44 (ITS), Buaraba (Leeson), and Buaraba Levers Road. These are in abeyance due to the DNR moratorium on future permits. Previous operations further upstream (Buaraba McDonald 1 and 2), which were carried out specifically for the Lake Clarendon project have closed in recent years.

Lockyer Creek Very small intermittent operations are present in many of the other streams in the Helidon - Gatton region. The largest pit is CSR Dinner Corner, a large offstream pit near Grantham. The coarse aggregate (gravel) component is unsuitable. for concrete due to the high percentage of unsound sandstone particles (DPI, 1995b ).

Helidon Sand Supplies (N. Roots) extracts sand and some gravel from Sandy Creek, creating a large on-stream lake. Production is about 18,000 t/yr but can be affected by drought due to lack of processing water (DPI, 1995b ). Some of the product can be used as concrete sand.

Pine River The Pine Rivers area has been a major source of natural aggregate for the Brisbane market since the early 1970s. Potential deposits were outlined in Hofmann and others (1976), Hofmann (1977, 1980) on the basis of a reconnaissance drilling program of the North and South Pine Rivers carried out in the mid 1970s. This study provided the background resource information for a planning study (Cameron McNamara and Partners, 1978) which established a strategy for extraction and rehabilitation (Co-ordinator Generals Department, 1978).

Considerable volumes of material have been removed since Hofmann (1980) reported potentially extractable resources of 72 Mt of mixed fine and coarse aggregate in the ratio of 23 6:4. Potential deposits were reviewed in O'Flynn and others (1983) but the resource figure was not revised.

Since that time urban development and subsequent extraction has further reduced the available resources but no comprehensive review of the current available reserves was possible in O'Flynn's (1992) review nor in the present survey.

Lawnton (Boral): Boral Resources (Qld) Pty Ltd operate the extensive Lawnton Pits (Fig. 2) initially commenced by the original Readymix Group. The workings comprise a series of large offstream lakes on the southern bank of the North Pine River which have been worked for mixed sand and gravel by dragline and more recently suction dredge to a depth as great as 12m below waterline. Overburden up to 4 m thick is removed by excavator. Material extracted is washed and screened at the nearby plant, with oversize material being crushed and reclassified.

Production comprises 350 000 t/yr of coarse sand and gravel (ratio of 7:3 sand to gravel) which is used largely by the company's concrete plants on the north side of Brisbane. About 200 000 t/yr of coarse sand is used for concrete, with an additional 45 000 t/yr for other products. About 105 000 t/yr river gravel is also produced, with 30 000 t/yr of fine sand collected from the wash tailings. Restrictions exist on the hours of work and when transport can operate, with different hours for summer and winter. The product is trucked via Gympie Road, with no more than 180 laden vehicles permitted during one week.

Most of the sand is marketed in Brisbane north of the Brisbane River, but some of the sand is supplied to the Sunshine Coast because of a dearth of similarly graded, coarse sand in that area.

Bald Hills (Pioneer): Pioneer's Pine River operations have moved from the APM Pit east of Petrie on the North Pine River to the lower South Pine River adjacent to the Bruce Highway north of Bald Hills. This area was extensively worked by Pioneer in the 1980s under agreement with Ariadne Australia Pty Ltd. A large on-stream lake system has been created.

Overburden is removed by excavator or dragline and dump trucks. Sand and gravel are extracted by dragline or dredge. Raw product is crushed, screened, classified and washed on site. Products are trucked directly onto the Bruce Highway to service the Brisbane region market on the northern side of the Brisbane River.

Production is currently 150 000 t/yr total, comprising 97 000 t/yr crushed gravel aggregate and 53 000 t/yr of coarse sand for ready-mixed concrete. Ninety percent of both products are used internally for Pioneer Concrete and 10% is marketed externally.

Neilsens (Brendale): Neilsen's Quality Gravels Pty Ltd operate a large system of offstream pits on the northern alluvial terraces of the South Pine River upstream of the rail 24 line west of Strathpine and Bald Hills. Clay overburden is stripped by endloader prior to extraction by dragline (or excavators in the vicinity of powerlines which traverse the deposit). The mixed aggregate is washed and classified, and oversize which comprises a significant proportion of the material is crushed and reclassified.

Production was about 300 000 t/yr of medium to coarse sand and gravel in the early 1990s (O'Flynn, 1992). The proportion of coarse sand has been about 55%. Current production is about 200 000 - 250 000 t/yr of total sand and gravel, with about 100 000 - 150 000 t/yr of coarse sand.

Products are supplied to concrete plants, including their own (Neilsen's Concrete Pty Ltd), although quantities of sand were formerly used in asphalt. Significant amounts of drainage gravel are also included. Until recently the company supplied sand to Excel who have a concrete plant close by.

Pine River (East Coast Gravels): East Coast Gravels allowed their former permit to dredge the Pine River channel to lapse because of the pressure of environmental complaints. East Coast Gravels now operate an offstream lake system on the southern side of the South Pine River opposite its junction with the North Pine River. Production at present is only 72 000 t/yr coarse sand and gravel due to the economic downturn.

Coomera River CSR Oxenford: The area upstream and immediately downstream of the town of Upper Coomera has a long history of sand and gravel extraction by CSR, formerly as The Readymix Group and as Sellars Holdings. A large system of on-stream lakes has been created. Nucrush Gravels also extracted lesser quantities in the Upper Coomera area.

Production by CSR from the Upper Coomera area is now probably minor. The once centrally located plant has been moved to the active Gambamora site (Oxenford Sand and Gravel) on the southern side of the Coomera River just upstream of the Pacific Highway bridge.

Overburden is removed by excavator and front end loader, and is transported by dump trucks and road trucks. Sand and gravel is extracted by dragline, suction dredge, and excavator. Processing comprises crushing, screening, washing, dewatering, and blending. The products are transported in 27 t payload semi-trailer and truck & dog road trucks via the Oxenford - Coomera Road onto the Pacific Highway to supply the Brisbane and Gold Coast markets.

About 300 000 to 400 000 t/yr of total sand and gravel are produced, comprising about 300 000 to 350 000 t/yr of coarse sand, with 20 000 to 50 000 t/yr of crushed gravel as coarse aggregate. 25

Logan River The Logan River drains mainly Mesozoic age sandstones and mudstones of the Clarence­ Moreton basin, and is not a viable producer of coarse sand. Although significant resources of fine-medium sand are present, the proportion of coarse sand is minor (Kinhill Cameron McNamara Pty. Ltd., 1990; Hollingsworth Dames & Moore, 1994).

Mary River The Mary River is a major source of aggregate for the Sunshine Coast and Hervey Bay (DPI, 1995a; Waye, 1993). The rapid growth in these areas has led to a corresponding growth in demand for aggregates, particularly coarse sand for use in concrete. Production from tidal (150 000 t/yr) and non-tidal sections (150 000 t/yr) provides about 300 000 t/yr.

However, the only section of the river that bears on coarse sand supply and demand for the Brisbane region and market is the section upstream of Gympie. Here the production has been about 1 050 000 t of sand and gravel (DPI, 1995a). Most of this has been over the five years 1989-1993, at about 120 000 t/yr with about 70 000 t/yr of coarse sand.

Other Sources Clutha Sands: Clutha Sands produce coarse sand from sandstone adjacent to Clutha Creek southwest of Beenleigh. Weathered sandstone of the Woogaroo Subgroup is dry ripped by dozer and sluiced to produce several grades of sand from fine to coarse. Production rates are unknown but believed to be small.

Ravensbourne Pit: Kansas Properties operate the Ravensboume Pit in a weathered medium grained sandstone. The pit supplies concrete products, plaster and bedding sand for the Toowoomba market (DPI, 1995b). Production rates are unknown, but large resources remain.

Manufactured Sand Pioneer (Wolffdene), Hymix (Nerang), Excel (Glasshouse), Boral (Narangba and Stapylton), CSR (Beenleigh, Petrie and Tweed) and Nucrush (Oxenford) already use manufactured sand or a more basic crusher dust in concrete plants.

Wolffdene Quarry (Pioneer): Pioneer has begun production at a new $20 million crushing and screening plant at the Wolffdene Quarry, 40 km south of Brisbane. A master computer controlled system maximises quality, productivity and safety. Manufactured sand is produced along with the now traditional gravel-sized coarse aggregate and road base materials.

The manufactured sand is produced by crushing a hard greywacke rock type into a sand­ sized fine aggregate(< 5 mm). The manufactured sand is not simply 'crusher dust', which 26 is a by-product of coarse aggregate manufacture. After coarse crushing and screening, the aggregate is purposely crushed with 4 stages of Nordberg cone crushers to produce a controlled envelope of graded particle sizes with a cubical shape (rather than the flaky or elongate shapes produced as 'crusher dust' by-product).

Pilot tests in a quartzite rock type at the Wolffdene quarry in 1996 showed that the 'waste' fines from the manufactured sand washing process could be used in brick manufacture, and thus lessen the potential environmental problems of waste fines disposal. However, so far Wolffdene (Pioneer) has not needed to wash the manufactured sand product when crushing good quality greywacke, because the product only has 12% fines, which is acceptable in concrete and improves its workability. Therefore, the Wolffdene plant has switched the wash plant off, and has not yet needed to use fines in brick manufacture to overcome the waste fines issue as originally planned.

All Pioneer concrete plants south ofthe Brisbane River (except West End) already use only manufactured sand in concrete to service Brisbane to the Gold Coast markets (J. Smith, Pioneer, pers. comm., July 1997). The Pioneer West End plant was still using river sand for a particular contract recently and could not change the specification mid-job. Within a short time the West End plant will also be using manufactured sand (J. Smith, Pioneer, pers. comm., July 1997). It is not known whether significant quantities of natural fine sand are blended with the manufactured sand.

The current production rate is 450 000 t/yr of manufactured sand.

Stapylton/ Narangba Quarries (Boral): Boral have been producing 'manufactured sand' /crusher dust for the past 2 years, but not in large quantities and only up to 50% blended with natural coarse sand. Research has been ongoing on technical issues for further developing manufactured sand technology for Boral' s use. Production rates are currently 50 000 t/yr for each quarry, producing a total of 100 000 t/yr of manufactured sand.

Glasshouse Quarry (Excel): Excel have been using manufactured sand from their Glasshouse Quarry for the past 6 months for all their coarse sand needs, whereas they previously bought coarse natural sand from Neilsens (Brendale). The concrete mix requires increased amounts of natural fine sand to be blended with the manufactured coarse sand and the coarse crushed rock aggregate.

A Nordberg cone crusher was trialled for 1 year, but was later replaced by a vertical shaft impact crusher, which has provided better results (J. Johnson, Excel, pers. comm., 1997). The new crusher uses the particles themselves to assist particle size reduction and produces good particle shapes. As a result, the cement paste content for concrete is the same or reduced by up to 5%. Water content in the concrete has not increased because the < 75 microns fines are less than 8-10%, and are 'stone flour', not clay minerals reacting with the 27 water. The 28 day strength for 20 MPa concrete has improved by 1.5 MPa (J. Johnson, Excel, pers. comm., 1997).

The current production rate is 140 000 t/yr of manufactured sand, from a total quarry throughput of coarse and fine aggregates of 450 000 t/yr. The Glasshouse Quarry has produced up to 500 000 t/yr in years of good demand, and as little as 200 000 t/yr in conditions of economic downturn.

Nerang (Hymix) Quarry: The Nerang (Hymix) Quarry has also started producing manufactured sand. About 50 000 to 80 000 t/yr are currently being produced. Although it is basically crusher dust that is cyclone washed, the product meets the standard specification for concrete aggregate. Hymix will be carrying out detailed monitoring of shrinkage and cracking performance in the warmer summer months to come.

FUTURE DEMAND

Controls on Coarse Sand Demand In estimating past and present demand as a guide to future demand, it is assumed that past and present production is generally representative of demand. Demand for coarse sand, like other rock construction materials, is controlled by population growth and the state of the construction industry, especially the demand for concrete.

The health of the construction industry has been cyclical in tune with regional and global trends, but on a local scale the extractive materials sector can be affected by major infrastructure projects which increase demand for short periods. Large infrastructure projects are more likely to come online in upcycle periods of economic growth, thus adding to the already high short term demand.

Demand Estimates for Total Sand & Gravel Several estimates are available for total sand and gravel production for the Brisbane region, which is taken as the Brisbane and Moreton Statistical Divisions.

Dames & Moore (1997) quote Australian Bureau of Statistics (ABS) production figures from 1987 to 1993 of 5.4 to 8.1 Mt/yr of total sand and gravel, and a DPI estimate for 1994 of 5.25 Mt/yr. These ABS figures appear to include fine-medium sand.

SKM (1997) quote ABS figures for 1990 of7.3 Mt of fine and coarse sand and gravel for the Brisbane and Moreton Divisions. DPI (1995b) estimated the 1990 production at 6.6 Mt/yr oftotal sand and gravel. 28 Dames & Moore (1997) quote ABS figures for 1992-93, during the recent economic upcycle as 8.07 Mt of total sand and gravel, comprising 5.364 Mt total sand (fine and coarse), with 2.707 Mt of gravel.

SKM (1997) quote aBoral internal research estimate for coarse sand and gravel (fine sand excluded) in 1995-96 at 4.2 Mt/yr. This figure seems reasonable for the economic downcycle which had already begun in 1995-96.

Demand Estimates for Coarse Sand J. Johnson (Excel, pers. comm., 1997) has provided the following estimate for a good economic situation: Coarse Sand Pre-mix concrete at 4 Mm3/yr 2.5 Mt/yr Concrete products and asphalt 1.5 Mt/yr Total 4.0 Mt/yr

SKM ( 1997) quote an internal Boral estimate for coarse sand for 1995-96 (economic downcycle )at 2.4 Mt/yr.

The present survey of mainly company data supplemented by recent DNR figures accounts for a coarse sand production rate for 1997 of 2.6 Mt/yr (see Table 2, p. 43), and thus closely accords with the Boral estimate.

Relying largely on the ABS estimates for 1992-93 of 8.07 Mt total sand and gravel including 2. 7 Mt of gravel, the Boral estimate of 2.4 Mt, and the present survey estimate of 2.6 Mt of coarse sand for 1995-97, I estimate the following annual demands:

Gravel Coarse Sand Fine Sand Total 33% 48% 19% Mt Mt Mt Mt Economic downcycle (1995-97) 1.8 2.6 1.0 5.4 Economic upcycle (1990-95) 2.7 3.9 1.5 8.1 Note: Key data are highlighted.

Future Demand Estimates Dames & Moore (1997) use the ABS production totals for 1987 to 1993, together with population data to calculate an average annual consumption of all sand and gravel of 3.84 t/capita. The 1994 downcycle year with DPI production data yields a figure of 2.6 t/capita, and the upcycle years yield a figure of 4.1 t/capita .

. h il 11 Jlll!l 29 Dames & Moore (1997) used the average consumption rate of 3.84 t/capita, together with the DLGP low, medium and high population forecasts to estimate a demand for 2001 of 9 to 9.5 Mt total sand and gravel.

Using my estimates of the gravel: coarse sand: fine sand proportions above yields the following demands for 2001: Gravel Coarse Sand Fine Sand Total 33% 48% 19% Mt Mt Mt Mt Year 2001 3.1 4.5 1.8 9.4

It should be noted that these forecasts are based on 1990s data where the production ratio of natural gravel: manufactured gravel was probably changing just as the ratio of natural coarse sand: manufactured sand is changing right now. Much of the river gravel demand in 2001 may be capable of being replaced by crushed rock coarse aggregate, and some of the natural coarse sand may be capable of being replaced by crushed rock fine aggregate (manufactured sand). Natural fine sand will not be capable of being replaced in that time period, and will be in higher demand under a scenario of widespread manufactured sand (see later).

FUTURE RESOURCES As stated in the introduction, to be available for the period 1997-2000, any individual coarse sand resource has to have all land and access controls and operational approvals in place now to be relevant to this issue. Other resources are mentioned in this report only for completeness.

Alternative sources of coarse sand within economic transport distances of Brisbane are limited. Existing sources of similar natural sand, chiefly the Pine Rivers, Coomera River, Mary River and non-tidal reaches and alluvial flats of the Brisbane River near Ipswich are themselves limited and are already committed in companies' business plans. There are sizeable volumes known in the channel of the upper Brisbane River north of Toogoolawah. However, it is believed that the Department of Natural Resources, after a management study, will be imposing upper limits on production rates so as to protect the ecology of the stream bed. These amounts could in fact be less than those currently permitted. There may be resources beneath some of the alluvial flats of this agricultural area, but few investigations have been carried out to date to determine their size and acceptability of working, and no inventory of resources has been possible.

Remaining Resources of the Brisbane River Tidal Reaches

O'Flynn (1992) reviewed previous investigations of sand and gravel resources in the tidal reaches, particularly based on Holmes (1980). He estimated that 13.6 Mm3 (20.4 Mt) remained in 1991 in reaches open to extraction. Assuming extraction rates of 600 000 t/yr to 30 1.2 Mt/yr over the past 6 years, about 13-17 Mt possibly remains, although Boral have estimated the amount in reaches that could be made available to further dredging as 5.6 Mt (see Table 3). The remaining resource is therefore very significant from a regional perspective.

Modern Rates of Brisbane River Sand Supply Coarse sand and gravel are present on the bed from above the tidal limit to New Farm, but do not reach the river mouth. Fine sand and mud reach the delta front at the river mouth and have formed an extensive delta of tidal flats topped by low beach ridges fronted by a prodelta mud apron.

Stephens (1992) has estimated the long term supply ofmud from the Brisbane River over the past 6 500 years as a minimum of 175 000 t/yr, but there have been no previous estimates of fine sand supply. Fine sand has formed tidal flat deposits beneath the delta plain stretching back to Hamilton, as well as the modern tidal flats and delta front bars. The supply of fine sand to these deposits has been estimated from data in Evans (1990), Stephens (1992), Jones and Holmes (1986) and Searle and others (1986). The area of fine sand from Hamilton to Fishermans Island to Shorncliffe is estimated at 9 300 ha averaging 2.5 m thick, calculated as 232 Mm3 or 325 Mt (at 1.4 tim\ providing an average rate of 50 000 t/yr over 6 500 years of present sea level conditions.

The sediment transport fluxes that have produced the pattern of coarse sand and gravel within the river are unknown. However, if mud is supplied at 175 000 t/yr and fine sand at about 50 000 t/yr, the long term rate of supply of coarse sand and gravel to the tidal reaches may have been quite low.

DPI (1995c) estimates the present coarse sand and gravel supply rate since the building of Wivenhoe Dam to be insignificant at about 1 000 m3/yr (1 500 t/yr). The long term average rate prior to the dam appears to have been about 4 000 m3/yr (6 000 t/yr) (DPI, 1995c: Table 2). This average rate takes into account large fluctuations due to flood events. It is likely that the major hydrodynamic changes resulting from dam building and river mouth dredging are likely to have upset the longitudinal equilibrium between such minor fluvial sand gains and losses. The predicted long term natural supply rate of 6 000 t/yr would have produced about 39 Mt total during the past 6 500 years of present sea level. However, Malempre (1989) estimated total reserves in the tidal reaches as over 100 Mt.

These figures suggest that much of the coarse sand and gravel in the tidal reaches predates modern conditions, and presumably was deposited as sea level rose 10 000 to 6 500 years ago. The late Holocene component has been extracted already (over 40 Mt had been extracted by the end of 1989 according to Malempre, 1990). Hence the continued extraction of coarse sand and gravel at rates above the 6 000 t/yr natural supply rate is eating into a sub-fossil and non-renewable resource. After floods the sand deposits appear 31 to have been replenished, but this is really only a redistribution of the pre-existing bed material.

Since the resource is exposed on the bed of the estuary it is subject to the modem tidal regime. Extraction during the last few decades has presumably been re-equilibrating the estuary bed to the changing tidal regime. Further dredging is likely to continue altering the balance between tidal transport and river flow within the estuary, but the impacts are likely to be no more (and possibly less) than the changes already experienced over the last few decades due to river mouth dredging and dam building.

Brisbane River Catchment Upstream Channels and Alluvial Flats

Priors Pocket to Wivenhoe Priors Pocket Pit: Indicated resources are 0.5 Mt of variable quality including patches of mud (Table 3). The planned future production rate is 300 000 t/yr with an estimated resource life of less than 2 years to June 1999. Boral are yet to receive approval from BCC for extension of time to complete the extraction and rehabilitation by June 1999 as planned.

The company has planned a sequence of overburden stripping, extraction, and rehabilitation which will ultimately result in a large lake for recreational use on the lower area and a residential development on the higher ground. The lake will be a permanent low flow, self-flushing system. Some of the area will become public open space rehabilitated with trees.

Between Colleges Crossing and Lake Wivenhoe, DPI (1995c) reviewed in-stream deposits at 34 sites, 13 of which hold significant reserves totalling 1.3 Mm3 (2 Mt).

Two small floodplain resources of about 0.4 to 0.3 Mt each occur on BCC land between the Mount Crosby Weir and Kholo bridge, and could be worked by trucking raw product to nearby processing plants (J. Johnson, Excel, pers. comm., 1997). These were also described in DPI (1995c ).

Kholo Deposit: CSR Readymix have made application to extract sand and gravel from an abandoned channel/ low terrace upstream of the Kholo Bridge, adjacent to the area previously draglined by Sellars Holdings Ltd and CSR' s current loam working. CSR has applied to work the deposit by extending the excavation to form an on-stream lake. Inferred resources are estimated at about 0.9 Mt.

Sapling Pocket/ Summerville Pits: Significant resources remain in the upper terrace, abandoned channel and remnants of the lower terrace adjacent to the river. Inferred 32 resources are 0.85 Mt at Sapling Pocket and 1.5 Mt at Summerville Pit, and would be sufficient for 8-10 years supply at current extraction rates.

Andrews Pit: Although resources above water level are now depleted, about 450 000 t of sandy gravel are present below water level (DPI, 1995c ). If DNR permits continued extraction from above the base flow level only (see later), the remaining resources available for extraction would be small.

The alluvial terrace geology suggests that further off-stream resources may occur under agricultural land on both sides of the river, but no information on these areas was found during the present survey.

Fernvale Pit: Boral's Femvale Pit is approved but not yet operating. Overburden up to 4 m thick will be removed with scrapers, excavators and dozers. Extraction of sand and gravel will be by excavators and dozers. The raw material will be trucked to Boral' s 17 Mile Rocks plant via the Brisbane Valley Highway - Warrego Highway - Centenary Highway (L. Armitstead, Boral, pers. comm., 1997). The raw material will then be screened, classified, with later washing and crushing as needed.

Measured resources are 2 Mt of sand and gravel (Table 3), and is of reasonable quality. Planned future production is 250 000 to 300 000 t/yr, whereby the resource will probably last for 7-1 0 years. End use will be for a lake and agriculture. The site has town planning approval for 300 000 t/yr production, but Department of Environment approval is currently only for 100 000 t/yr. Because the resource is small (7 years life), Boral maintain that it would not be economical to build a plant capable of more than 300 000 t/yr (L. Armitstead, Boral, pers. comm., 1997).

The deposit is a key resource in Boral's coarse sand strategy, as it will be their only natural sand deposit after completion of Priors Pocket and the tidal reaches dredging. Both of the other two major companies have natural sand deposits, ie Bald Hills (Pioneer) and Oxenford-Gambarnora (CSR). Boral believe it is essential for them to maintain the life of this resource as long as possible to assist in the transition from sand to blended manufactured sand to 100% manufactured sand. Boral believe there will also be a continuing need for some natural sand for specialised concrete, and wish to maintain the Femvale resource for this specialised supply over the long term. They do not want to rapidly deplete the resource as an alternative to tidal reaches sand after October 1997 (L. Armitstead, Boral, pers. comm., 1997).

Wivenhoe Pocket: About 150 000 t of sand and gravel remain ·within the high banks in an area of past extraction by several operators (DPI, 1995c ). However off-stream resources have not been assessed and may be inferred to be more significant, although they would be constrained by prime agricultural land use.

1irlli I. f 33 Camerons Crossing: About 300 000 t of sand and gravel are present within the high banks above water level (DPI, 1995c ), but significant off-stream resources are inferred under agricultural land.

Lake Wivenhoe: Resources of sand and gravel remain in the former channels of the river that are now submerged within the ponded area of the Wivenhoe Dam. These deposits, once part of the active system, are now in the category of sub-fossil resources. The deposits could be located using historical records and marine seismic and drilling techniques. However, long-term future extraction would require major environmental investigations to ensure no adverse effects on water quality etc.

Wivenhoe Upstream The Department of Natural Resources has recently carried out an inventory of coarse sand and gravel resources in the Upper Brisbane River between Monsildale Creek and the headwaters ofLake Wivenhoe (Waye, 1997).

In-stream deposits on low 'floodplains' and benches occur semi-continuously between Monsildale Creek and the headwaters of Lake Wivenhoe (Waye, 1997). The deposits are probably 5-10 m thick, with a total geological inferred resource of about 50 Mm3 (75 Mt using a conversion of 1m3 = 1.5 t). Most of this is not extractable due to environmental constraints. It is likely that only floodplain or bench deposits above the base flow river level will be made available for extraction by the Department of Natural Resources (J. Dale, foreword in Waye, 1997). This also means that the current production rate from these deposits is likely to fall as a result of the new management regime. The in-stream geological inferred resource above base flow level is about 4.8 Mm3 or 7.2 Mt (Waye, 1997) (see Table 3), but even this amount is not likely to be made available for extraction due to the potential for localised bank erosion at some sites.

Moorabool Pit (AMTD 248-246): The Moorabool resource extends about 2 km downstream of the Twin Bridge. A low floodplain on the inside of the Moorabool meander (left bank) contains about 600 000 t above base flow level.

Note: "AMTD" below refers to DNR 's Adopted Middle Thread Distance from the Brisbane River mouth in kilometres.

Twin Bridge (AMTD 250-248): Upstream of the Twin Bridge a 100 m wide floodplain about 5-6 m above the base flow level contains about 450 000 t of sand and gravel. (Note: This location is not the "Twin Bridges" at Femvale.)

Gregors Creek Bridge (AMTD 252-251): The low floodplain within an incised meander downstream of the bridge has been worked by several operators, but still contains about 330 000 t of sand and gravel to base flow level. 34

Sinnamon Lane (AMTD 254): A floodplain deposit on the inside of a minor meander at the Karreman operation contains only about 75 000 t above base flow level.

Moore Island (AMTD 271): Adjacent to The Round Mountain at Moore, an in-stream island of sandy gravel lies between twin channels of the Brisbane River. The island forms a low floodplain rising to about 4 m above base flow, and a geological inferred resource of about 600 000 t of sandy gravel is likely.

Linville (AMTD 281-279): Four stripped floodplain deposits near Linville contain a geological inferred resource of about 750 000 t of sandy gravel above the base level river flow.

Off-stream resources have not been investigated under modern economic or environmental constraints. It is probable that several deposits over 1 Mt occur in low terraces adjacent to the main Upper Brisbane River channel.

Buaraba Creek Holmes (1979) outlined large deposits of sand and subsidiary gravel on sections of the creek upstream of Atkinsons Dam based on the results of limited reconnaissance drilling. The upstream deposit consists of up to 6.5 m of gravel and sand with negligible overburden while the downstream deposit comprises at least 4.2 m of sand and gravel under 1.6 to 3.0 m of sandy clay overburden.

Buaraba (Nucrush): Nucrush (Brisbane Valley Sand & Gravel) have inferred resources of 1 Mt of excellent quality medium-coarse sand (Table 3). The sand has a high quartz content, is sharp, and ideally graded for concrete. Cement paste savings are possible making the sand very cost effective in concrete (D. Gray, Nucrush, pers. comm., 1997). The quality of the sand makes the deposit viable even though the markets in Toowoomba, Brisbane, and the Gold Coast are distant. The furthest haulage distance is 180 km at which the economics are marginal. At a planned production rate of 60 000 to 120 000 t/yr (30 000 to 80 000 t/yr coarse sand), the deposit has a maximum life of 10 years.

The resource is under potential constraints due to agricultural land policy, constraints on haulage hours of operating, farmer concerns with water supplies, and community concern with truck movements on local roads. The planned end use is as water storage for agriculture.

No other estimates for Buaraba Creek's in-stream or off-stream resources are available. 35

Cressbrook Creek Applications to extract off-stream resources have been made at "Strathdee" at the junction with the Brisbane River, and upstream of Toogoolawah at "Wirralee", but the later application is in abeyance. DPI (1995b) indicate that applications have also been made for in-stream extraction.

It can be inferred from the alluvial geology, DPI soils mapping, reconnaissance investigations by Holmes (1979), and the above site investigations that Cressbrook Creek probably contains significant off-stream resources, much of them under prime agricultural land.

Pine River Lawnton (Boral): Indicated resources are 2.5 Mt (Table 3), and will be adequate for 7 years at the current extraction rate of 350 000 t/yr.

Bald Hills (Pioneer): Measured resources are 1.5 Mt, with a 10 year resource life at the planned production rate of 97 000 t/yr gravel and 53 000 t/yr coarse sand. The site will be rehabilitated as parkland as an end use.

Neilsens (Brendale): Alberton Investments Pty Ltd (a Neilsen company as landowner) has applied for an extension to the current operations on adjacent land (Lot 88). Remaining resources at the current pits are unknown, but should be about 2 Mt, with an additional measured resource of 1 Mt on the adjacent Lot 88 application, for a total resource of about 3 Mt (3.8 Mt according to Boral's lAS report - Lloyd Consulting and others, 1997).

Pine River (East Coast Gravels): Indicated resources are 2.5 Mt of sand and gravel (Table 3).

Coomera River CSR (Oxenford): Good quality sand overlying river gravel is interspersed with marine and terrestrial clay bands, especially towards the downstream end of the Gambamora deposit. Indicated resources of 3 Mt are present in the active site and will last about 10 years subject to any major infrastructure projects. Another 4 Mt of inferred and indicated resources are approved for extraction upstream, for a total of 7 Mt which comprises a very significant resource on the regional scale. End use is the Coomera Lakes real estate development.

Coomera River Channel: A large in-stream resource of coarse sand remains within the Coomera River channel between Brygon Creek and the Pacific Highway. Nucrush applied for approval to extract from this site 5 years ago, originally via the Department of Transport (O'Flynn, 1992). Approval from the current administrative authority, the 36 Department of Environment has not yet been obtained, and residential encroachment may soon alienate this deposit.

Mary River The reserve base of sand and gravel in the Mary River valley is about 100 Mm3 (150 Mt); with only 5% recoverable due to economic and/or environmental constraints (DPI, 1995a). Therefore, about 7.5 Mt could be considered as total reserves, with the major deposits at Kenilworth (1.5 Mt) (Table 3) and Miva (2.25 Mt).

To supply the Brisbane market, Mary River sand could be transported at increased costs of about $14/t from Kenilworth (110 km * $0.13/t) and $23/t from Miva (180 km * $0.13/t). However, the demand in the Hervey Bay region is such that the latter resource should be used in that area.

Other Sources Clutha: O'Flynn (1992) reported that large resources of weathered coarse sandstone were present at the site in 1989, although no information was available on the lateral and vertical extent of rippable material. In any case extraction of a surficial layer of weathered sandstone may not be environmentally acceptable on a large scale.

Helidon: Several investigations have been carried out on the possibility of extracting coarse sand from weathered Woogaroo Subgroup sandstone in the Helidon and Redbank Plains area. Problems include inferior strength and high water demand in concrete product, as well as environmental problems with waste fines disposal. No commercially viable operations have commenced.

Manufactured Sand Extensive resources of hardrock occur in operating and approved quarries in southeast Queensland. Commercial production of manufactured sand or commercial use of an improved form of crusher dust has commenced at Wolffdene (Pioneer), Glasshouse (Excel), Nerang (Hymix), Stapylton (Boral), Narangba (Boral), Petrie (CSR), Beenleigh (CSR), Tweed (CSR), and Oxenford (Nucrush). Some of these produce manufactured sand at a high level of technical sophistication for use in pre-mixed concrete( eg Pioneer), while some others merely utilise some of their crusher dust blended with natural sand.

A very large and regionally significant hardrock resource containing rock suitable for manufactured sand occurs at Kholo Creek straddling the Brisbane/ Ipswich City boundary. This resource has no extractive approvals, but is presently being evaluated to determine whether haul route problems can be overcome. However it may be several years before any operations could commence.

The aggregates used in concrete can have a major effect on the durability of concrete. The following properties affect concrete: particle density, percentage of fines, clay coatings of 37 grains, organic material, particle size distribution (grading), particle strength, reactivity with alkalis, particle shape, and porosity (QCL, internet data, 1997). AS 2758.1 Concrete Aggregates requires that uncrushed fine aggregate (natural sand) has less than 5% finer than 75 microns.

There are three mam stages in the production of manufactured sand: crushing, washing/classifying to produce correct particle size gradings, and what to do with waste fines (slimes). The three main factors affecting concrete production and placement are workability, quality, and cost (Hudson, 1996a). These categories have an inter­ dependence. For example, if more cement paste is added to a concrete mix, it will increase its quality, at the expense of workability and cost. Likewise, adding more water to increase workability and thus lower raw material cost, also lowers quality, and the extra water may cause particle segregation and bleeding of water from the concrete.

As a general rule, the higher the cement paste: water ratio, the higher is the concrete quality, as measured by compressive strength, durability, impermeability, and resistance to abrasion and chemical attack.

Hudson (1996a) strongly advocates the need for cubical or equidimensional particle shapes to increase the cement paste: water ratio, and thus decrease the costs of production and placement, and increase the workability without decreasing quality or increasing raw material cost.

The shape, angularity, and surface texture of aggregate particles all affect the volume of cement paste needed to both fill voids and float the aggregate. Good cubical shape in the coarse aggregate allows concrete of given workability to be produced with a smaller volume of cement paste, and hence lower total cost.

However, the impact of physical properties is even more important in the fine aggregate fraction of a concrete mix. The greatly increased surface area to volume ratio amplifies any undesirable shape or texture properties in both the plastic and hardened states of concrete. Through their effect on cement paste content and water demand to fill voids, cubical-shaped aggregate particles enhance workability, compressive and flexural strength, and reduce shrinkage and cracking.

The most important impliCation of this is that not all rock types have the mineralogy and petrology to allow the production of cubical particles (eg greenstones usually), no matter what crusher technology is used, a fact not discussed at all by Hudson (1996a, b), who markets vertical impact crusher technology.

The majority of crusher dusts, traditional by-products of coarse aggregate crushing, are extremely angular, flaky or elongated. However, true manufactured sands are completely different from both crusher dust and natural sand, and must be treated accordingly (Hudson, 1996b ). Although there has been undoubted prejudice in the concrete industry 38 against manufactured sand, Pioneer have had virtually no complaints from concrete customers.

Rough-surfaced cubical particles assist the cement paste - aggregate particle bonding, present less surface per unit volume, and produce tighter packing, with minimum water demand per unit cement paste to get the concrete workable in its plastic state. Maximum packing is produced by having minimum volume of voids between aggregate particles. Minimum void space can be achieved only with a well graded particle size distribution matched to the particle shape, where smaller particles neatly fill the voids between larger particles, which neatly fill the voids between yet larger particles, and so on.

With angular manufactured sand a higher proportion of75 to 150 micron size is required to fill the voids. However, overseas research has shown that the 75 to 150 micron fraction (very fine sand size) in manufactured sand does not increase water demand, and can increase workability and compressive strength. For these associated particle shape reasons, there will be an increased demand for fine natural sand when manufactured sand becomes commonplace. Excel's experience is that the natural coarse sand replacement reduces 3 3 from 600-650 kg/m to 500-550 kg/m , and the natural fine sand requirement of 300- 380 kg/m3 increases by an equivalent amount to 400-480 kg/m3 to (J. Johnson, pers. comm, 1997).

The less than 75 micron fraction ('stone flour') in manufactured sand also does not affect water demand until it exceeds 15%. Such proportions also decrease water bleeding problems and increase compressive strength (Hudson, 1996b). However, the capacity to use such high percentages of <75 microns material is also dependent on the grading and quality of that <75 micron fraction (J. Hunt, Boral, pers. comm., 1997). If the <75 micron material comprises clay type minerals, then water demand, and hence cement paste requirements will rise. If the fine cut off can be made at 50 microns, to exclude the finest clay size grades, then fewer problems arise. This presents technical problems because hydraulic classifiers in common use, which are used to remove clay size material from natural sands, also remove significant quantities of <150 micron range, thus wasting valuable product.

Concrete finishing has been a problem with manufactured sand elsewhere. This can be overcome to a large extent by ensuring cubical particle shape and sufficient 75 to 150 micron fraction (Hudson, 1996b), but can also be improved at additional cost through the use of plasticisers.

The problem of concrete bleeding has not been solved with manufactured sand. This is a form of segregation caused by settling of the solids without entrainment of their proper water content, where some of the water rises to the surface of freshly placed concrete. The control of this problem has to be matched against the control of surface water evaporation which causes concrete shrinkage especially in hot windy placement conditions. 39 Hudson ( 1996b) states that the critical area of control of shrinkage and bleeding is the quality of the particle shape. If particles are not cubical, they will tend to produce concrete that has excessive water bleeding due to a high initial water demand to achieve a desired workability. Shrinkage can be partly overcome through the application of curing membranes or covers (at increased cost).

The particle size distribution and the particle shape are also controlled by the crusher technology. Vertical shaft impactors simulate attrition in nature through rock particle fracturing rock particle, thus also decreasing wear on crusher parts, and perform better than cone crushers (Hudson, 1996b ). This mainly applies to performance with respect to particle shape, whereas cone crushers can provide better grading (J. Hunt, Boral, pers. comm., 1997). The rock-on-rock action of vertical shaft impactors also rounds off the corners of correctly sized particles, thus producing more waste than is necessary.

The manufactured sands currently produced at Wolffdene (Pioneer) and Nerang (Hymix) are in dense greywacke rock types and at Glasshouse (Excel) in a very dense and hard crystal lithic tuff rock type. Comparisons of manufactured sand produced using different crushing technology, but from a similar greywacke rock type has produced similar grading and quality results (D. Gray, Nucrush, pers. comm., 1997). Thus rock type may be even more important than particle shape, and hence more important than crushing and washing/grading technologies. This may be due to rock fracturing into particles sizes according to the remnant grainsizes inherent in the rock. For example a coarse grained granite may fracture easily into coarse sand, whereas a greenstone may preferentially fracture into fine elongate particles.

Because of the variety of rock types m Bora!' s approved resource areas, eg granite, hornfels, quartzite, and greenstone, it will take some time to complete research on the balances between particle size distribution versus shape and texture, cement paste and water demand to produce economically viable manufactured sands. Boral will need time to research which crusher technologies and washing/classifying treatments are possible with their various rock types.

G. Williams (Hymix, pers. comm., 1997) has stated that although coarse aggregates could be kept in the crushing cycle, at present the production rate of manufactured sand is controlled by the ability to sell the co-produced coarse aggregate. However, Pioneer's Wolffdene plant is flexible enough to increase the manufactured sand output by recirculating coarse material and thus tailor production to meet sales demand.

Thus there are differing views on the status of manufactured sand technology in southeast Queensland, and its effects on the supply and demand of natural coarse and fine sand. However, all major operators are moving towards the use of manufactured sand for the majority of their future coarse sand requirements. 40

CAPACITY OF KNOWN RESOURCES TO SUPPLY THE SHORTFALL Kinhill Economics ( 1995) evaluated the economic significance of CSR' s Sapling Pocket resource, as well as the economic impacts of licence refusal. They used a 50 km haulage radius as the maximum haulage distance for sand and gravel based on industry experience, although recognising that materials may be carted longer distance at times of strong demand or for some specific product grades.

The denial of access to resources in any one area means that available resources elsewhere will be placed under greater stress, the extractive industry and ultimately the building industry will incur increased transport costs from more distant sources (Kinhill Economics, ( 1995). All of the alternatives, both manufactured sand and more distant natural sand sources will impose additional costs on producers, the building industry and through them, on the community. Any short term increases in costs due to longer haulage will ultimately be passed on to the community which utilises the resource in finalised products. The community would also face increased costs through workforce dislocation and increased commuting distance for remaining workers (Kinhill Economics, (1995).

Bora/'s Own Capacity to Make Up the Bora/ 11Case 2" Shortfall Case 2 involves forced cessation of tidal reaches dredging from October 1997. Boral' s lAS report indicates measures they would/could put in place to make up part of the Boral shortfall resulting from such a closure.

For 1997 a shortfall of about -125 000 t would remain and would be directly related to ceased dredging.

In 1998 the 400 000 t shortfall in tidal reaches dredging could be decreased to a total shortfall of -200 000 t by bringing Femvale on line a year earlier to produce 150 000 t, as well as increasing planned production of manufactured sand at Stapylton by 50 000 t.

In 1999 the 400 000 t shortfall in tidal reaches production could be decreased to a total shortfall of -150 000 t by maintaining the production rate at Lawnton to 50 000 t more than originally planned, by accelerating production increases of manufactured sand at Narangba by 50 000 t, by accelerating production increases at Femvale by 50 000 t, and by accelerating production increases of manufactured sand at Stapylton.

These measures represent a major commitment in research and capital outlays, but will still leave Boral with shortfalls of 125 000 t in 1997, 200 000 t in 1998, and 150 000 t in 1999. Coarse sand could be supplied from other operators, either directly to the market or via Boral purchasing sand from the other operators to maintain their market share.

The direct cost to Boral of the 475 000 t total shortfall is said to be about $8.55 million at $18/t sale price (SKM, 1997, p. 48 and 55). However, the net cost to Boral would be less

Pi n111 n nvJI m atrrmr •• f Plilllil .,.,.. 41 than $8.55 million because of lower production and transport costs. The net cost actually represents only lost profits and any premium above the average market sale price that Boral might be forced to pay to maintain their market share. The real costs to Boral include the capital costs to bring forward production at their other natural and manufactured sand sites. This would amount to $15.5 million for Case 2 versus $7.5 million for the Base Case to 1999, or $8 million over the 3 years (see Table 6.19 of Boral lAS - Lloyd Consulting and others, 1997). These costs would potentially be passed on to consumers.

However, the possibility of more wide-reaching and long term implications for resource management and future supplies are discussed below.

Firstly, the effects on Boral's resources would be: Bora/ Lawnton - depletion of the resource in 2006, 9 months earlier than planned. Bora/ Priors Pocket - no change. Bora/ Narangba - long term extra production of 50 000 t, which is really only a nominal value representing Boral's original intention to maintain a production capability in the tidal reaches. Bora/ Fernvale - very little change, with the resource depleted by 2007, but with 50 000 t less production that final year. Bora/ Stapylton- depletion of resource by 2014, two years earlier than planned. Bora/ Ormeau - start of manufactured sand production by 2002, 5 years earlier than planned, but with negligible effects on long term resource management.

It is clear that Boral might take several measures to ameliorate the effects on their production and resource management if dredging were to cease in October 1997. Common sense suggests that such measures would undoubtedly be costly for manufactured sand research and for bringing forward capital investment. The effects on resource depletion are set out above, and are not drastic for Boral although they have not been costed financially. Notwithstanding Boral' s efforts there will remain some shortfalls of 125 000 t in 1997, 200 000 t in 1998, and 150 000 t in 1999 for other producers to make up.

Other Operators' Capacity to Make Up the Borai"Base Case" Shortfall The following describes how other operators might make up the shortfalls assuming the proposed production rates of Boral' s original business plan. This assumes that Boral are not able to implement the strategies of their Case 2 scenario. The planned production from the Brisbane River tidal reaches is 450 000 t/yr sand and gravel, comprising about 80% coarse sand (360 000 t/yr) (see Table 2). In 1998 and 1999 this shortfall would have been partly made up in Boral' s original plan (base case) by increasing manufactured sand output from Stapylton and by bringing Fernvale online in 1999 when Priors Pocket is completed. This plan would result in larger shortfalls than in Boral's Case 2 scenario (see Table 2).

Pioneer Wolffdene - current production of manufactured sand from Pioneer's Wolffdene Quarry is 450 000 t/yr matched to sales (P. Martin, Pioneer, pers. comm., 1997). The 42 maximum production rate is 500 000 t/yr, but is tied into the demand for the associated coarse aggregate produced by the hardrock crushing process. Hence Pioneer could only supply an additional 50 000 t/yr at maximum production.

Pioneer Bald Hills - Current production from Pioneer's Bald Hills plant is 53 000 t/yr coarse sand (fine aggregate) and 97 000 t/yr coarse aggregate (150 000 t/yr total). Although no increases in production rate are planned, the current maximum production rate is 230 000 t/yr, which assuming a similar fine : coarse aggregate ratio would result in 81 000 t/yr coarse sand. Operating at maximum current plant rate would supply an additional 28 000 t/yr.

Pioneer Hillcrest Quarry - If Pioneer's planned Hillcrest Quarry at Dayboro can be approved, developed, and operating by 1999, it will also be able to produce manufactured sand to supplement Boral' s shortfall in 1999.

CSR Summerville/ Sapling Pocket/ Kholo - CSR's Tivoli plant services Summervilles/ Sapling Pocket Pits and the Kholo Pit, as well as the Sugarloaf Quarry at Mutdapilly. Current production of fine aggregate (natural coarse sand and a small amount of manufactured sand) is about 200 000 to 300 000 t/yr, as well as natural coarse aggregate (river gravel) and crushed coarse aggregate etc (CSR have supplied more detailed figures to the author on a commercial-in-confidence basis, as have Hymix, Nucrush, and Neilsens for their operations).

Planned future production of fine aggregate is 250 000 to 350 000 t/yr, supplying only an additional 40 000 t/yr of coarse sand. The Tivoli plant is under urban encroachment and would probably not be upgraded without difficulty. Therefore, throughput is unlikely to be significantly increased. Alternative methods at the pits could produce short term significant increases in coarse sand production (R. Bendall, CSR, pers. comm., 1997).

CSR Oxenford - CSR' s Oxenford plant produces about 150 000 t/yr of natural coarse sand and gravel from the Coomera site and 210 000 t/yr coarse sand and gravel from the Oxenford Sand & Soil (Gambamora) site (SKM, 1997). Confidential information provided by CSR is similar to the SKM estimates. The coarse sand component is about 85%, with a total coarse sand supply rate of about 300 000 to 350 000 t/yr.

Although there is about 7 Mt of inferred and indicated resources, planned future production rates are subject to major projects in southeast Queensland. Maximum production capacity could be raised to 350 000 to 450 000 t/yr with minimal effort, with an additional supply capacity of 100 000 t/yr of coarse sand (R. Bendall, CSR Construction Materials, pers. comm., 1997). 43

Table 2. Coarse Sand Production and Additional Supply Capacity, Brisbane Region 1997: Non-Confidential version Name of Operation Operator Current Production Current Production Extra Coarse Sand Supply (t/yr) 4 (t/yr) Capacity (t/yr) 3 Fine Aggregate 2 Fine Aggregate 1997 1998 1999 Brisbane River tidal reaches Bora! 360,000 I 360,000 -125,000 -320,000 -320,000 Lawnton Pit Bora! 245,000 245,000 0 0 0 Priors Pocket Pit Bora! 210,000 210,000 0 0 -200,000 Femvale Pit Bora! 0 0 0 0 190,000 Stapylton Quarry Bora! 50,000 50,000 0 50,000 100,000 Narangba Quarry Bora! 50,000 50,000 0 0 0 Boral Total 915,000 915,000 -125,000 -270,000 -230,000 Sapling Pocket/ CSR Readymix 200,000 to 300,000 250,000 to 350,000 40,000 40,000 40,000 Summervilles Pits Oxenford & Coomera Pits CSR Readymix 300,000 to 350,000 350,000 to 400,000 100,000 100,000 100,000 Bald Hills Pits Pioneer 50,000 80,000 30,000 30,000 30,000 Wolffdene Quarry 5 Pioneer 450,000 500,00C 50,000 50,000 50,000 Nerang Quarry Hymix 50,000 to 80,000 50,000 to 80,00C 0 0 0 Neilsens Pit Neilsens 100,000 to 150,000 150,000 to 250,000 70,000 70,000 70,000 Pine River (East Coast) East Coast Gravels 50,000 140,000 90,000 90,000 90,000 Glasshouse Quarry Excel 140,000 200,00C 60,000 60,000 60,000 Buaraba (Nucrush) Nucrush 30,000 to 80,000 50,000 to 100,000 30,000 30,000 30,000 Buaraba Creek other vanous 30,000 30,000 0 0 0 Brisbane River above vanous 40,000 50,00C 10,000 10,000 10,000 Wivenhoe 6 Upper Mary River 6 vanous 70,000 S,OOC 0 0 0 Others Sub-Total 1,650,000 2,065,00U 480,000 480,000 480,000 Total 2,565,000 2,980,000 355,000 210,000 250,000 Notes: 1 - Based on Boral's original business plan (Base Case) 2 - Includes natural and manufactured coarse sand 3 - Current production capacity assumes immediate capability with no upgrades to plant 4- Extra supply is current (notional) capacity less current production. 5 - Manufactured sand shown in italics. 6 - The Mary River and the Upper Brisbane River may be restricted to natural replenishment rates in the future. 44

Neilsens - Neilsens Quality gravels produces about 200 000 to 250 000 t/yr of coarse sand and gravel for about 100 000 to 150 000 t/yr of coarse sand. Production is below capacity due to the economic downcycle and Excel's use of its own manufactured sand. Neilsen's additional capacity is about 70 000 t/yr of coarse sand.

East Coast - East Coast Gravels produces only 50 000 t/yr of coarse sand at present due to the economic downcycle, and could produce an additional 90 000 t/yr of coarse sand.

Excel - Excel are currently producing 140 000 t/yr of manufactured sand from their Glasshouse Quarry. If the total capacity of co-produced coarse aggregates could be marketed, an additional 60 000 t/yr of manufactured sand could be produced.

Nucrush - Nucrush at Buaraba Creek could provide an additional 30 000 t/yr of coarse sand into western Brisbane (D. Gray, Nucrush, pers. comm., 1997).

Other Brisbane River and Buaraba Creek producers - In-stream production from Buaraba Creek is already over the natural replenishment rate, and the upper Brisbane River could provide only an additional 10 000 t/yr if in-stream production was geared more towards coarse sand rather than coarse sand and gravel. The present in-stream production rates may be decreased in the future due to demands on riverine management. However, jurisdictional control of extraction rates could also be subject to legal argument regarding the definition of the high banks.

It can be seen from Table 2 that about 480 000 t/yr of coarse sand could be supplied by operators other than Boral to supply the shortfalls in 1997 to 1999 should Boral have to cease .dredging the tidal reaches. However, if the current production rate of 70 000 t/yr coarse sand from the upper Mary River was decreased to the long term natural replenishment rate of 5 000 t/yr, there would be a further shortfall of 65 000 t/yr. It is reiterated that this analysis is based on current maximum production capacity of other operators without extra capital investment in plant, as such costs might be passed onto consumers.

The major potential suppliers of additional coarse sand, should Boral have to cease dredging the river, would be CSR (Oxenford) who work off-stream lakes on the Coomera River, East Coast Gravels and Neilsens Quality Gravels, both of which work offstream lake operations on the South . Pine River. Transport costs from the Coomera River might increase for supply into Brisbane City, but transport from the Pine Rivers area should not be a prohibitive factor.

Pioneer maintain that manufactured sand production costs at Wolffdene Quarry are no greater than for their previous Brisbane River dredging operations (J. Smith, Pioneer, pers. comm., 1997). This has presumably been due to the economies of scale and automation of the new plant, despite the increased energy costs for crushing hard rock. However, Kinhill Economics ( 1995) concluded that an additional cost for rock crushing of $7/t would increase costs to final customers by 30%. Transport costs from the Wolffdene area may not be a prohibiting factor. However, Kinhill Economics (1995) concluded that if the similarly distant CSR Sapling Pocket licence was not approved, an additional 45 30 km haulage distance for the 300 000 t/yr of coarse sand would result in extra costs of $1.2 million/year at 13 cents/tonne/km.

Transport of manufactured sand from Glasshouse (Excel) and natural sand from Buaraba Creek and the upper Brisbane River would presumably increase the final costs due to the extra transport distance. However, in the case of manufactured sand from the Glasshouse and Nerang (Hymix) quarries, it seems that even mid-sized companies, if vertically integrated, can deliver concrete competitively over considerable distances to the Brisbane City area.

Thus the answer to the question "Could potential shortfalls from Boral having to leave the river, be supplied from available alternative sources?" is "Yes, in the short term 1997 to 1999". The resource depletion impacts on Boral itself would be present but have not been cos ted.

The impact of additional demand on other companies, such as East Coast Gravels, Neilsens, CSR, Pioneer, and perhaps Nucrush may be to use up their natural coarse sand resources earlier than planned, but in time scales longer than the 1997-1999 period (see Table 3). Boral may also wish to protect their market share by buying sand from other producers. For competitive reasons, Boral may not wish to buy sand from smaller independent producers (after Neilsens became competitors in concrete supply, Excel no longer bought natural coarse sand from them).

Current manufactured sand producers feel that the quality of concrete will not be adversely affected by use of· manufactured sand. However some of them and some companies not yet producing manufactured sand believe that some natural coarse sand will be necessary for high specification products in the immediate future. The industry members appear to be somewhat divided on the finer details ofthe range and quality of products that will be possible with manufactured sand.

Expected Longer Term Increases in Demand This analysis has focussed only on supply and demand for the period 1997 to 1999, but the forecasts of population growth and a predicted return to economic growth in the construction and housing industries shows that demand for coarse sand resources will increase substantially in the next couple of decades.

This analysis suggests that 4.5 Mt of coarse sand might be required in southeast Queensland by 2001. The present supply is 2.6 Mt and the present capacity is about 3.0 Mt. Thus unless further natural sand resources can be approved or there is a dramatic increase in manufactured sand production, there might be a significant shortfall in coarse sand supply by 2001, which will be unrelated to Boral's tidal reaches operations. The capital costs for Pioneer's Wolffdene plant have been reported at $20 million. Since this was for a entire coarse aggregate-fine aggregate plant, the capital costs to other new manufactured sand plants might be more like $1 0-15 million. Simple economics suggest that these capital costs might be passed on to the consumer inevitably, however, the market dictates what customers pay in the short term. Although only 1.15 Mt more sand is proposed by Boral to be dredged from the river, their removal from the tidal reaches will exacerbate the long term shortfall. 46 Dames & Moore (1997) provide estimates of future demand for total sand and gravel: 10.5-11.9 Mt in 2011, and 12-14.4 Mt in 2021.

At 48% of total sand and gravel, the coarse sand component of these projections are: 5.0-5.7 Mt in 2011, and 5.8-6.9 Mt in 2021.

Thus there are likely to be large increases in coarse sand demand brought about by population growth, as well as a cyclical return to economic growth. Any loss of Brisbane River tidal resources may exacerbate the resulting pressure on other resources.

T a bl e 3 . N aura t I C oarse S an dResources, B"bns ane R egwn . 1997 Name of Operation Sand + Gravel Resource Life at Resource Life at Market Resource (Mt) Current Max. Production Production (yr) Capacity (yr) Boral: Brisbane River tidal 5.6 12 12 Bw,Bc, reaches Bs,GC Lawnton Pit 2.5 7 7 Bn,SC Priors Pocket Pit 0.5 2 2 Bw,Bs Fernvale Pit 2.0 not operating 7 Bw,Bs Other Operators: Sapling Pocket/ 2.4 8 7 Bw,Bs Summervilles Pits Oxenford & Coomera 7.0 20 16 GC,Bs Pits Bald Hills Pits 1.5 10 7 Bn Neilsens Pit 3.0 14 9 Bn Pine River (East 2.5 35 11 Bn Coast) Buaraba (Nucrush) 1.0 8 6 Bw,Bs, GC Buaraba Creek other small? short? short? Bw,Bs Brisbane River above 7.2 100? 40? Bw,Bs, Wivenhoe Bn,SC Mary River (upper) 1.5 15 214 SC,Bn

Note: Bw, Brisbane west; Bn, Brisbane north; Bs, Brisbane south; Be, Brisbane central; SC, Sunshine Coast; GC, Gold Coast.

* Not all of this is likely to available due to localised bank erosion concerns at some sites. Hence at the present rate of production, the expected resource life may be decreased. 47

RESOURCE PLANNING It is clear that known resources of natural coarse sand will not be adequate for continued future supply. Existing in-stream resources are in jeopardy due to environmental concerns. In tidal estuaries not significantly altered by navigational dredging, such environmental concerns might not be so serious, although this is yet to be established through proper environmental investigations.

Off-stream resources in alluvial terraces and floodplain benches offer more opportunity from an environmental point of view, except that they usually coincide with prime agricultural or residential land. Extraction of some sand resource followed by rehabilitation and creation of water storages has potential for re-use of agricultural land. However, it remains to be established whether both sand extraction and agriculture can be sequential uses. In any case there is virtually no information on regional-scale off-stream resources for southeast Queensland.

It is therefore critical that further sterilisation of known and potential sand resources by alienating land uses be prevented by giving suitable planning protection.

The trend towards increasing use of manufactured sand will transfer the resource planning problems from in-stream and off-stream natural sand and gravel onto hardrock resources. Total approved hardrock resources in southeast Queensland are estimated at 786 Mt (D. Kershaw, Kershaw & Co., pers. comm., 1997). At an average consumption rate of 7.25 t/capita estimated from DME production statistics, these resources will be exhausted by 2026 using the DLGP medium series population projections (or within 20 to 30 years at low to high series projections). These interpretations refer to the regional scale, and some individual resources will provide materials for up to 100 years (eg Wolffdene and Narangba), while smaller existing quarries may be exhausted much sooner than 20 years. Extractive companies own land containing another 400 Mt of hardrock resources (D. Kershaw, pers. comm., 1997), but operational approvals for these cannot be guaranteed.

It is clear therefore that existing resource approvals can only cater for one generation. To cater for just two generations will require the production and consumption of 1.4 billion tonnes of hardrock by 2046, and an additional 700 Mt above existing known hardrock resources will be have to be found and secured for exploitation. 48 Over the past few decades the extractive industry has been hampered by a number of recurring problems including:-

inadequate protection of established operations from incompatible land uses, eg. encroachment of residential development resulting in land use conflict;

• inadequate protection of potential deposits with the resultant sterilisation of sources of supply by other land uses;

• difficulties in establishing new operations because the approval system discounted the regional significance of the operations; and

• inadequate treatment of environmental issues by some extractive industry operators or proponents.

To overcome some of these problems requires that resources of extractive materials be identified and evaluated in southeast Queensland. To ensure their availability for extraction, key resources and suitable buffers should then be protected from encroachment by alienating land uses via appropriate planning instruments. Suitable haul routes also require urgent planning protection. Planning protection may also be needed for screening and concrete batching plants to ensure that encroachment by alienating land uses is prevented.

Transport issues include not only the origin, but the destination of quarry materials including processing plants and customers. Haul routes need to be assessed within the framework of existing road networks and any load restrictions placed on local roads to prevent haul trucks within residential areas. The issues of greatest concern to local communities are noise, dust and road safety.

A State Planning Policy for Extractive Resources needs to be developed to ensure that town planning schemes provide for land use decisions that will ensure continued extraction and transport of extractive materials by industry for the community's use.

An Environmental Planning Policy for Extractive Resources also needs to be developed to ensure all extractive resources are managed to meet the needs of both present and future generations; to ensure the appropriate use of the most environmentally acceptable sources of supply; and to ensure best practice environmental performance by the extractive industry. 49

CONCLUSIONS Pioneer Concrete officially ceased operations on the tidal reaches of the Brisbane River in April 1997. Boral Ltd will cease in the next few years or sooner, depending on the outcome of several studies. If Boral has to cease dredging the river, there will be an immediate decrease in the supply of coarse sand.

Natural coarse sand is produced from small-scale operations in stream beds, to large-scale off-stream operations by major vertically integrated companies. The major operations are in the tidal in-stream and non-tidal off-stream deposits of the Brisbane River, Coomera River and Pine River.

Until the late 1970s, the Brisbane River provided virtually the only source of aggregate for concrete and other construction uses. In the last two decades, however, the proportion of gravel has steadily declined to about 20 percent, and has been replaced by crushed stone aggregate. The ongoing dredging of the Brisbane River from the early 1980s to the present has been essential not as a source of gravel, but for the continued supply of the coarse sand fraction for pre-mixed concrete.

Demand for coarse sand is controlled by population growth and the state of the construction industry which has been cyclical, especially the demand for concrete. From a variety of data the following demands are estimated: Gravel Coarse Sand Fine Sand Total Mt/yr Mt/yr Mt/yr Mt/yr Economic downcycle (1995-97) 1.8 2.6 1.0 5.4 Economic upcycle (1990-95) 2.7 3.9 1.5 8.1 Year 2001 3.1 4.5 1.8 9.4

Alternative sources of coarse sand within economic transport distances of Brisbane are limited. To be available for the period 1997-2000, any individual coarse sand resource has to have all land and access controls and operational approvals in place now to be relevant to this

ISSUe.

Existing sources of similar natural sand, chiefly the Pine Rivers, Coomera River, Mary River and non-tidal reaches and alluvial flats of the Brisbane River near Ipswich are themselves limited and are already committed. Resources of sand and gravel remain submerged within the Wivenhoe Dam. However, their long-term future extraction would require major environmental investigations. The in-stream ipferred resource above base flow level in the upper Brisbane River is 7.2 Mt, but much of this is unlikely to be made available for exploitation. No estimates for off-stream resources are available for the upper Brisbane River, Buaraba or Cressbrook Creeks. so Manufactured sand from hardrock quarries has recently begun to replace some of the natural sand in concrete. Pioneer (Wolffdene), Hymix (Nerang), Excel (Glasshouse), Boral (Narangba and Stapylton), CSR (Petrie, Beenleigh and Tweed), and Nucrush (Oxenford) already use manufactured sand or a more basic form similar to crusher dust in concrete plants.

The three mam factors affecting concrete production and placement are workability, quality, and cost. Hudson (1996a) strongly advocates the need for cubical or equidimensional particle shapes, which through their effect on cement paste content and water demand to fill voids, can enhance workability, compressive and flexural strength, and reduce shrinkage and cracking. Minimum void space can be achieved only with a well graded particle size distribution matched to the particle shape. The particle s1ze distribution and the particle shape are also controlled by the crusher technology.

However, not all rock types have the mineralogy and petrology to allow the production of cubical particles, no matter what crusher technology is used. Additionally, for particle shape reasons, there will be an increased demand for fine natural sand when manufactured sand becomes commonplace. Concrete finishing, water bleeding and shrinkage have been problems with manufactured sand elsewhere, but are controllable.

Except at the Wolffdene plant, the production rate of manufactured sand in hardrock quarries is also constrained at present by the ability to sell the co-produced coarse aggregate, because stockpiling it would be uneconomic. Thus there are complications and differing opinions concerning the status of manufactured sand technology in southeast Queensland, and its effects on the supply and demand of natural coarse and fine sand.

Because of the variety of Boral' s rock types, it will take some time to complete research on the balances between particle size distribution versus shape and texture, cement paste and water demand to produce economically viable manufactured sands. Boral will also need time to research crushing and screening/classifying technologies applicable to their various rock types.

About 480 000 t/yr of coarse sand could be supplied by operators other than Boral to supply the shortfalls in 1997 to 1999 should Boral have to cease dredging the tidal reaches. Should production in the upper Mary River be drastically cut for riverine management reasons, only 415 000 t/yr of coarse sand might be available from other operators. The assessment of what additional coarse sand other operators could supply assumes that current operations are not upgraded through capital investment in plant, since these costs might be passed on to the consumer via increased prices.

Should Boral's application to continue on the river be refused, the major potential suppliers of additional sand would be CSR (Oxenford and Summervilles), East Coast Gravels (Pine River), Neilsens Quality Gravels (Brendale), Excel (Glasshouse), Pioneer (Wolffdene and Bald Hills), Nucrush (Buaraba Creek) and to a lesser extent small 51 operators in the upper Brisbane River. Transport of manufactured sand from Glasshouse (Excel) and natural sand from Buaraba Creek and the upper Brisbane River might increase the final costs due to the extra transport distance.

Resource depletion impacts on Boral itself would be present but have not been costed. However, the resource depletion impacts on other companies, such as East Coast Gravels, Neilsens, CSR (Oxenford), Pioneer (Bald Hills) and perhaps Nucrush (Buaraba) could be to use up their resources earlier than planned, but in time scales longer than the 1997-1999 period.

The above assessment applies to the current economic downcycle conditions only. Forecasts of population growth and a predicted return to economic growth in the construction and housing industries suggests that demand for coarse sand resources will increase substantially in the next couple of decades. The present supply is 2.6 Mt/yr and the present capacity is about 3.0 Mt/yr. This analysis suggests that 4.5 Mt/yr of coarse sand might be required by 2001, 5.0-5.7 Mt/yr by 2011, and 5.8-6.9 Mt/yr by 2021.

Thus unless further natural sand resources can be approved or there is a dramatic increase in manufactured sand production, there might be a significant shortfall in coarse sand supply by 2001, which will be unrelated to Boral's tidal reaches operations. Capital costs to bring manufactured sand online might be passed on to the consumer in the long term. Any removal of Boral from the tidal reaches would exacerbate the situation.

It is clear that known resources of natural coarse sand will not be adequate for continued future supply. Existing in-stream resources are in jeopardy due to environmental concerns. Off-stream resources in alluvial terraces and floodplain benches offer more opportunity from an environmental point of view, but there is virtually no information on regional­ scale off-stream resources for southeast Queensland. It is therefore critical that further sterilisation of known and potential sand resources by alienating land uses be prevented by giving suitable planning protection.

The trend towards increasing use of manufactured sand will transfer the resource planning problems from in-stream and off-stream natural sand and gravel onto hardrock and fine sand resources. However, even the current bank of approved hardrock resources will be exhausted within 20 to 30 years, although the life of individual resources will vary from a few years to one hundred years. Extractive companies own other hardrock resources but there is no guarantee that operating approvals will be forthcoming.

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