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Home , Aggregate (geology), Air pollution, Extractive metallurgy, Heap leaching, Hydraulic mining, Mineral

1. Overview of and its Impacts1

Proposed mining projects vary according to the these are the subject of this Guidebook. type of or materials to be extracted from the The Guidebook does not discuss the mining of earth. The majority of proposed mining projects ores that are extracted using strip mining methods, involve the extraction of deposits such as including aluminum (), , and , , , , silver, , , . The Guidebook also does not discuss , and platinum. The environmental mining involving extraction of or aggregates, impacts of large-scale mining projects involving such as , , and .

1.1 PHASES OF A MINING PROJECT

There are different phases of a mining project, EIA for the exploratory of a mining project beginning with ore exploration and because the impacts of this phase can be ending with the post-closure period. What profound and because further phases of mining follows are the typical phases of a proposed may not ensue if exploration fails to find sufficient mining project. Each phase of mining is quantities of high-grade mineral ore deposits. associated with different sets of environmental impacts. 1.1.2 Development

1.1.1 Exploration If the mineral ore exploration phase proves that there is a large enough mineral ore deposit, of A mining project can only commence with sufficient grade, then the project proponent may knowledge of the extent and value of the mineral begin to plan for the development of the mine. ore deposit. Information about the location and This phase of the mining project has several value of the mineral ore deposit is obtained during distinct components. the exploration phase. This phase includes surveys, field studies, and drilling test boreholes 1.1.2.1 Construction of access and other exploratory excavations. The construction of access roads, either to The exploratory phase may involve clearing of provide and supplies to the wide areas of (typically in lines), to mine site or to out processed metals and allow the entry of heavy vehicles mounted with ores, can have substantial environmental impacts, drilling rigs. Many countries require a separate especially if access roads cut through ecologically

Chapter 1 3 sensitive areas or are near previously isolated In almost every case, metallic ores are buried communities. If a proposed mining project under a layer of ordinary or (called involves the construction of any access roads, then ‘overburden’ or ‘ rock’) that must be moved the environmental impact assessment (EIA) for the or excavated to allow access to the ore deposit. project must include a comprehensive assessment The first way in which proposed mining projects of the environmental and social impacts of these differ is the proposed method of moving or roads. excavating the overburden. What follows are brief descriptions of the most common methods.

1.1.3.1 Open-pit mining

Open-pit mining is a type of strip mining in which the ore deposit extends very deep in the ground, necessitating the removal of layer upon layer of overburden and ore.

In many cases, logging of trees and clear-cutting or burning of vegetation above the ore deposit may precede removal of the overburden. The use of heavy machinery, usually bulldozers and dump , is the most common means of near a mining , Pelambres mine, Chile removing overburden. Open-pit mining often PHOTO: Rocio Avila Fernandez involves the removal of natively vegetated areas, 1.1.2.2 Site preparation and clearing and is therefore among the most environmentally- destructive types of mining, especially within If a mine site is located in a remote, undeveloped tropical . area, the project proponent may need to begin by clearing for the construction of staging areas that would house project personnel and equipment. Even before any land is mined, activities associated with site preparation and clearing can have significant environmental impacts, especially if they are within or adjacent to ecologically sensitive areas. The EIA must assess, separately, the impacts associated with site preparation and clearing.

1.1.3 Active mining Open-pit mine in Cerro de Pasco, Peru Once a mining company has constructed PHOTO: Centro de Cultura Popular LABOR, Peru access roads and prepared staging areas that Because open-pit mining is employed for ore would house project personnel and equipment, deposits at a substantial depth underground, it mining may commence. All types of active usually involves the creation of a pit that extends mining share a common aspect: the extraction below the table. In this case, and concentration (or ) of a metal groundwater must be pumped out of the pit to from the earth. Proposed mining projects allow mining to take place. A pit usually differ considerably in the proposed method for forms at some point in time after mining stops and extracting and concentrating the metallic ore. the groundwater pumps are turned off.

4 Guidebook for Evaluating Mining Project EIAs 1.1.3.2 off-site. Mining projects that only involve the reworking of waste piles avoid Placer mining is used when the metal of interest the environmental impacts of open-pit mining is associated with in a or and placer mining, but still entail environmental . Bulldozers, dredges, or hydraulic jets impacts associated with purification (beneficiation) of (a process called ‘’) of metals from the waste piles. are used to extract the ore. Placer mining is usually aimed at removing gold from stream 1.1.4 Disposal of overburden and and . Because placer waste rock mining often occurs within a streambed, it is an environmentally-destructive type of mining, In almost every project, metallic ores are buried releasing large quantities of sediment that can under a layer of ordinary soil or rock (called impact for several miles downstream ‘overburden’ or ‘waste rock’) that must be moved of the placer mine. or excavated to allow access to the metallic ore deposit. For most mining projects, the quantity 1.1.3.3 Underground mining of overburden generated by mining is enormous. The ratio of the quantity of overburden to the In underground mining, a minimal amount of quantity of mineral ore (called the ‘strip ratio’) overburden is removed to gain access to the ore is usually greater than one, and can be much deposit. Access to this ore deposit is gained by higher. For example, if a proposed mining project tunnels or shafts. Tunnels or shafts lead to a more involves the extraction of 100 million metric tons horizontal network of underground tunnels that of mineral ore, then the proposed mining project directly access the ore. In an underground mining could generate more than one billion metric tons method called ‘’ or ‘block caving,’ sections of overburden and waste rock. or blocks of rock are removed in vertical strips that leave a connected underground cavity that is These high-volume , sometimes containing usually filled with cemented and waste significant levels of toxic substances, are usually rock. deposited on-site, either in piles on the surface or as backfill in open pits, or within underground Although underground mining is a less mines. Therefore, the EIA for a proposed mining environmentally-destructive means of gaining project must carefully assess the management access to an ore deposit, it is often more costly options and associated impacts of overburden and entails greater safety risks than strip mining, disposal. including open-pit mining. While most large- scale mining projects involve open-pit mining, 1.1.5 Ore extraction many large underground mines are in operation around the world. After a mining company has removed overburden, extraction of the mineral ore begins using 1.1.3.4 Reworking of inactive or specialized heavy equipment and machinery, abandoned mines and such as loaders, haulers, and dump trucks, which the ore to processing facilities using Some mining projects involve the reworking haul roads. This activity creates a unique set of waste piles (often tailings) from inactive or of environmental impacts, such as emissions of abandoned mines, or older waste piles at active fugitive from haul roads, which an EIA for a mines. Typically, this is proposed when more proposed mining project should assess separately. efficient methods of metal beneficiation have made it economical to re-extract metals from old mining waste. The material from the piles may be sent to processing facilities on-site or

Chapter 1 5 1.1.6 Beneficiation

Although metallic ores contain elevated levels of metals, they generate large quantities of waste. For example, the copper content of a good grade copper ore may be only one quarter of one percent. The gold content of a good grade gold ore may be only a few one-hundredths of a percent. Therefore, the next step in mining is grinding (or milling) the ore and separating the relatively small quantities of metal from the non- metallic material of the ore in a process called ‘beneficiation.’ Heap leach, Bighorn gold mine, CA PHOTO: Bender Environmental Consulting Milling is one of the most costly parts of 1.1.7 Tailings disposal beneficiation, and results in very fine that allow better extraction of the metal. However, As previously discussed, even high-grade mineral milling also allows a more complete release ores consist almost entirely of non-metallic of contaminants when these particles become materials and often contain undesired toxic tailings. Tailings are what remains following metals (such as , lead, and ). milling of the ore to fine particles and extraction of The beneficiation process generates high-volume the valuable metal(s). waste called ‘tailings,’ the residue of an ore that remains after it has been milled and the desired Beneficiation includes physical and/or metals have been extracted (e.g., with chemical separation techniques such as gravity (gold) or sulfuric (copper)). concentration, magnetic separation, electrostatic separation, flotation, extraction, If a mining project involves the extraction of a few , , , and hundred million metric tons of mineral ore, then amalgamation (often involving the use of the mine project will generate a similar quantity ). Wastes from these processes include of tailings. How a mining company disposes of waste rock dumps, tailings, heap leach materials this high-volume material is one of (for gold and silver operations), and dump leach the central questions that will determine whether materials (for copper leach operations). a proposed mining project is environmentally acceptable. The key long-term goal of tailings Leaching involving the use of cyanide is a kind disposal and management is to prevent the of beneficiation process, usually used with gold, mobilization and release into the environment of silver, and copper ores, that merits separate toxic constituents of the tailings. attention because of the serious environmental and public safety impacts. With leaching, finely An entire section of this Guidebook is devoted to ground ore is deposited in a large pile (called a detailed comparison of tailings disposal options a ‘leach pile’) on top of an impermeable pad, (see Section 3.2.1.3). These options include: (1) and a containing cyanide is sprayed on the use of a wet tailings impoundment facility or top of the pile. The cyanide solution dissolves ‘tailings pond’; (2) dewatering and disposal of the desired metals and the ‘pregnant’ solution dry tailings as backfill; and (3) sub-marine tailings containing the metal is collected from the bottom disposal. of the pile using a system of pipes. The first option (a tailings pond) is by far the most commonly used option, but the second option

6 Guidebook for Evaluating Mining Project EIAs (dry tailings disposal) is, in most circumstances, 1.1.8 Site reclamation and closure the environmentally-preferable option. The third option (sub-marine tailings disposal) is sometimes When active mining ceases, mine facilities and proposed with mine sites located near deep sea the site are reclaimed and closed. The goal of environments, or in rare instances in freshwater mine site reclamation and closure should always . Sub-marine tailings disposal has a poor be to return the site to a condition that most environmental record in the few instances where it resembles the pre-mining condition. Mines that has been practiced. are notorious for their immense impact on the environment often made impacts only during the Before the adoption of environmental laws closure phase, when active mining operations and standards, many mining companies simply ceased. These impacts can persist for decades dumped tailings in the nearest convenient and even centuries. Therefore, the EIA for every location, including nearby and streams. proposed mining project must include a detailed Some of the worst environmental consequences discussion of the mine Reclamation and Closure of mining have been associated with the open Plan offered by the mining proponent. dumping of tailings, a practice now nearly universally rejected. The International Finance Mine reclamation and closure plans must describe Corporation (IFC)/ Group explains: in sufficient detail how the mining company will restore the site to a condition that most resembles “Riverine (e.g., rivers, lakes, and lagoons) pre-mining ; how it will or shallow marine tailings disposal is not prevent – in perpetuity – the release of toxic considered good international contaminants from various mine facilities (such as practice. By extension, riverine which abandoned open pits and tailings impoundments); requires riverine tailings disposal is also not and how funds will be set aside to insure that the considered good international practice.”1 costs of reclamation and closure will be paid for.

An entire section of this Guidebook is devoted to a discussion of how to evaluate whether the Reclamation and Closure Plan offered by a mining proponent is adequate (see Section 3.7).

Wet tailings disposal at a mine in Peru PHOTO: Centro de Cultura Popular LABOR, Peru

1 IFC/World Bank (December 2007) “Environmental, and Safety Guidelines for Mining.” http://www.ifc.org/ ifcext/sustainability.nsf/AttachmentsByTitle/gui_EHSGuide- lines2007_Mining/$FILE/Final+-+Mining.pdf

Chapter 1 7 1.2 ENVIRONMENTAL AND SOCIAL IMPACTS OF MINING

The remainder of this chapter describes the most important environmental impacts of mining projects.

1.2.1 Impacts on water

Perhaps the most significant impact of a mining project is its effects on and availability of within the project area. Key questions are whether surface and groundwater supplies will remain fit for consumption, and whether the quality of surface in the project area will remain adequate to Acid mine drainage support native aquatic and terrestrial . PHOTO: SOSBlueWaters.org As Earthworks explains: 1.2.1.1 Acid mine drainage and contaminant leaching “Acid mine drainage is considered one of mining’s most serious threats to water The potential for acid mine drainage is a key resources. A mine with acid mine drainage has question. The answer will determine whether the potential for long-term devastating impacts a proposed mining project is environmentally on rivers, streams and aquatic life. acceptable. When mined materials (such as the walls of open pits and underground mines, “HOW DOES IT FORM? Acid mine drainage tailings, waste rock, and heap and dump leach is a concern at many metal mines, because materials) are excavated and exposed to metals such as gold, copper, silver and and water, acid can form if sulfide molybdenum, are often found in rock with (especially , or ‘fools gold’) are abundant sulfide minerals. When the sulfides in the rock and there is an insufficient amount of neutralizing are excavated and exposed to water and air material to counteract the acid formation. The during mining, they form . This acid will, in turn, leach or dissolve metals and acidic water can dissolve other harmful metals other contaminants from mined materials and in the surrounding rock. If uncontrolled, the form a solution that is acidic, high in sulfate, and acid mine drainage may runoff into streams metal-rich (including elevated concentrations of or rivers or leach into groundwater. Acid mine cadmium, copper, lead, zinc, arsenic, etc.) drainage may be released from any part of the mine where sulfides are exposed to air and Leaching of toxic constituents, such as arsenic, water, including waste rock piles, tailings, open selenium, and metals, can occur even if acidic pits, underground tunnels, and leach pads. conditions are not present. Elevated levels of cyanide and compounds (, “HARM TO FISH & OTHER AQUATIC LIFE: If , nitrite) can also be found in waters at mine mine waste is acid-generating, the impacts to sites, from and blasting. fish, and can be severe. Many streams impacted by acid mine drainage have Acid drainage and contaminant leaching is the a pH value of 4 or lower – similar to battery most important source of water quality impacts acid. Plants, animals, and fish are unlikely to related to metallic ore mining. survive in streams such as this.

8 Guidebook for Evaluating Mining Project EIAs “TOXIC METALS: Acid mine drainage also According to a study commissioned by the dissolves toxic metals, such as copper, : aluminum, cadmium, arsenic, lead and mercury, from the surrounding rock. These “Because of the large area of land disturbed metals, particularly the iron, may coat the by mining operations and the large quantities stream bottom with an orange-red colored of earthen materials exposed at sites, erosion slime called yellowboy. Even in very small can be a major concern at hardrock mining amounts, metals can be toxic to and sites. Consequently, must be wildlife. Carried in water, the metals can travel considered from the beginning of operations far, contaminating streams and groundwater through completion of reclamation. Erosion for great distances. The impacts to aquatic life may cause significant loading of sediments may range from immediate fish kills to sub- (and any entrained chemical ) to lethal, impacts affecting growth, behavior or nearby waterbodies, especially during severe the ability to reproduce. events and high melt periods.

“Metals are particularly problematic because “Sediment-laden typically they do not break down in the environment. originates as sheet flow and collects in They settle to the bottom and persist in the rills, natural channels or , or artificial stream for long periods of time, providing conveyances. The ultimate deposition of the a long-term source of to the sediment may occur in surface waters or it may aquatic insects that live there, and the fish that be deposited within the floodplains of a stream feed on them. valley. Historically, erosion and sedimentation processes have caused the build-up of thick “PERPETUAL : Acid mine drainage layers of mineral fines and sediment within is particularly harmful because it can continue regional and the alteration of indefinitely causing damage long after mining aquatic habitat and the loss of storage capacity has ended. Due to the severity of water within surface waters. The main factors quality impacts from acid mine drainage, many influencing erosion includes the volume and hardrock mines across the west require water velocity of runoff from precipitation events, treatment in perpetuity. Even with existing the rate of precipitation downward technology, acid mine drainage is virtually through the soil, the amount of vegetative impossible to stop once the reactions begin. cover, the slope length or the distance from To permit an acid generating mine means that the point of origin of overland flow to the point future generations will take responsibility for where deposition begins, and operational a mine that must be managed for possibly erosion control structures. hundreds of years.”2 “Major sources of erosion/sediment loading at mining sites can include open pit areas, 1.2.1.2 Erosion of and mine wastes heap and dump leaches, waste rock and into surface waters overburden piles, tailings piles and , haul roads and access roads, ore stockpiles, For most mining projects, the potential of soil vehicle and equipment maintenance areas, and sediment eroding into and degrading surface exploration areas, and reclamation areas. A water quality is a serious problem. further concern is that exposed materials from mining operations (mine workings, wastes, contaminated soils, etc.) may contribute sediments with chemical pollutants, principally . The variability in natural 2 Earthworks Fact Sheet: Hardrock Mining and Acid Mine Drainage. http://www.earthworksaction.org/pubs/FS_AMD.pdf

Chapter 1 9 site conditions (e.g., , vegetation, the slope to be revegetated either naturally or topography, , and proximity to and with human assistance.”3 characteristics of surface waters), combined with significant differences in the quantities and characteristics of exposed materials at mines, preclude any generalisation of the quantities and characteristics of sediment loading.

“The types of impacts associated with erosion and sedimentation are numerous, typically producing both short-term and long- term impacts. In surface waters, elevated concentrations of particulate matter in the water column can produce both chronic and acute toxic effects in fish. Overburden drainage at an Australian mine “Sediments deposited in layers in flood plains PHOTO: Peripitus or terrestrial can produce many impacts associated with surface waters, ground Environment summarizes the problem as water, and terrestrial ecosystems. Minerals follows: associated with deposited sediments may depress the pH of surface runoff thereby “Potentially adverse effects of inadequate mobilising heavy metals that can infiltrate minesite water management and design into the surrounding or can be carried include: unacceptably high levels of suspended away to nearby surface waters. The associated (Non-Filterable Residue) and dissolved impacts could include substantial pH solids (Filterable Residue) in surface runoff or metals loading to surface waters [and] bed and bank erosion in waterways. It and/or persistent contamination of ground is self-evident that a Sediment and Erosion water sources. Contaminated sediments may Control Plan is a fundamental component of a also lower the pH of soils to the extent that Minesite Water Management Plan.”4 vegetation and suitable habitat are lost. 1.2.1.3 Impacts of tailing impoundments, “Beyond the potential for impacts on waste rock, heap leach, and dump leach human and aquatic life, there are potential facilities physical impacts associated with the increased runoff velocities and volumes from new land The impacts of wet tailings impoundments, disturbance activities. Increased velocities and waste rock, heap leach, and dump leach volumes can lead to downstream flooding, facilities on water quality can be severe. These scouring of stream channels, and structural impacts include contamination of groundwater damage to bridge footings and culvert entries. beneath these facilities and surface waters. In areas where air emissions have deposited Toxic substances can leach from these facilities, acidic particles and the native vegetation percolate through the ground, and contaminate has been destroyed, runoff has the potential groundwater, especially if the bottom of these to increase the rate of erosion and lead to facilities are not fitted with an impermeable liner. removal of soil from the affected area. This 3 MINEO Consortium (2000) “Review of potential envi- is particularly true where the is ronmental and social impact of mining” http://www2.brgm.fr/ characterised by steep and rocky slopes. Once mineo/UserNeed/IMPACTS.pdf the soils have been removed, it is difficult for 4 Environment Australia (2002) “Overview of Best Practice Environmental Management in Mining.” http://www.ret.gov.au/ resources/Documents/LPSDP/BPEMOverview.pdf

10 Guidebook for Evaluating Mining Project EIAs Tailings (a by-product of metallic ore processing) in a study commissioned by the European Union: is a high-volume waste that can contain harmful quantities of toxic substances, including arsenic, “Mine water is produced when the water table lead, cadmium, , nickel, and cyanide is higher than the underground mine workings (if cyanide leaching is used). Although it is rarely or the depth of an open pit surface mine. the environmentally-preferable option, most When this occurs, the water must be pumped mining companies dispose of tailings by mixing out of the mine. Alternatively, water may be them with water (to form a slurry) and disposing pumped from wells surrounding the mine to of the slurry behind a tall in a large wet create a cone of depression in the ground tailings impoundment. Because the ore is usually water table, thereby reducing infiltration. When extracted as a slurry, the resulting waste contains the mine is operational, mine water must be large amounts of water, and generally forms continually removed from the mine to facilitate ponds at the top of the tailings dams that can be the removal of the ore. However, once mining a threat to wildlife. Cyanide tailings in precious operations end, the removal and management metals mines are particularly dangerous. of mine water often end, resulting in possible accumulation in rock fractures, shafts, tunnels, Ultimately, tailing ponds will either dry, in arid and open pits and uncontrolled releases to the , or may release contaminated water, in environment. wet climates. In both cases, specific management techniques are required to close these waste “Ground water drawdown and associated repositories and reduce environmental threats. impacts to surface waters and nearby wetlands can be a serious concern in some areas. During periods of heavy , more water may enter a tailings impoundment than it has the “Impacts from ground water drawdown may capacity to contain, necessitating the release of include reduction or elimination of surface tailings impoundment effluent. Since this effluent water flows; degradation of surface water can contain toxic substances, the release of this quality and beneficial uses; degradation of effluent can seriously degrade water quality of habitat (not only riparian zones, springs, and surrounding rivers and streams, especially if the other wetland habitats, but also upland habitats effluent is not treated prior to discharge. such as greasewood as ground water levels decline below the deep root zone); reduced or Dozens of dam breaks at wet tailings eliminated production in domestic supply wells; impoundments have created some of the worst water quality/quantity problems associated environmental consequences of all industrial with discharge of the pumped ground water accidents. When wet tailings impoundments back into surface waters downstream from fail, they release large quantities of toxic waters the dewatered area. The impacts could that can kill aquatic life and drinking last for many decades. While dewatering is water supplies for many miles downstream of the occurring, discharge of the pumped water, impoundment. after appropriate treatment, can often be used to mitigate adverse effects on surface waters. 1.2.1.4 Impacts of mine dewatering However, when dewatering ceases, the cones of depression may take many decades to When an open pit intersects the water table, recharge and may continue to reduce surface groundwater flows into the open pit. For mining flows …. Mitigation measures that rely on the to proceed, mining companies must pump and use of pumped water to create wetlands may 5 discharge this water to another location. Pumping only last as long as dewatering occurs.” and discharging mine water causes a unique set of environmental impacts that are well described 5 MINEO Consortium (2000) “Review of potential envi- ronmental and social impact of mining” http://www2.brgm.fr/ mineo/UserNeed/IMPACTS.pdf

Chapter 1 11 1.2.2 Impacts of mining projects materials that generate hazardous air pollutants on air quality such as particulate matter, heavy metals, , dioxide, and nitrogen . Airborne emissions occur during each stage of the mine cycle, but especially during exploration, 1.2.2.1 Mobile sources development, construction, and operational activities. Mining operations mobilize large Mobile sources of air pollutants include heavy amounts of material, and waste piles containing vehicles used in excavation operations, that small size particles are easily dispersed by the transport personnel at the mining site, and trucks . that transport mining materials. The level of polluting emissions from these sources depends The largest sources of in mining on the fuel and conditions of the equipment. Even operations are: though individual emissions can be relatively small, collectively these emissions can be of real • Particulate matter transported by the concern. In addition, mobile sources are a major wind as a result of excavations, blasting, source of particulate matter, carbon monoxide, transportation of materials, wind erosion and volatile organic compounds that contribute (more frequent in open-pit mining), fugitive significantly to the formation of ground-level dust from tailings facilities, stockpiles, . waste dumps, and haul roads. Exhaust emissions from mobile sources (cars, 1.2.2.2 Stationary sources trucks, heavy equipment) raise these particulate levels; and The main gaseous emissions are from of fuels in power generation installations, and • Gas emissions from the combustion drying, , and operations. Many of fuels in stationary and mobile sources, producers of precious metals smelt metal on-site, explosions, and . prior to shipping to off-site refineries. Typically, gold and silver is produced in melting/fluxing furnaces that may produce elevated levels of Once pollutants enter the , they airborne mercury, arsenic, , and undergo physical and chemical changes before other metals. reaching a receptor (Figure 1). These pollutants can cause serious effects to people’s health and to 1.2.2.3 Fugitive emissions the environment.

The U.S. Environmental Protection Agency defines Large-scale mining has the potential to contribute ‘fugitive emissions’ as “those emissions which significantly to air pollution, especially in the could not reasonably pass through a stack, operation phase. All activities during ore chimney, vent or other functionally-equivalent extraction, processing, handling, and transport depend on equipment, generators, processes, and

Figure 1.

Impacts Emissions Atmosphere Human health, Mobile and stationary sources. Pollutants are transported, diluted, Environment (water, soil, wildlife), (Can be measured and controlled) undergo physical and chemical changes Infrastructure, Global climate

12 Guidebook for Evaluating Mining Project EIAs opening.”6 Common sources of fugitive emissions Volatilization of mercury from active heaps and include: storage and handling of materials; mine tailings facilities has recently been identified as processing; , blasting, construction another substantial source of mercury emitted to activities, and roadways associated with mining the atmosphere. This process should be assessed activities; leach pads, and tailing piles and ponds; and controlled. Overall, mercury present in gold and waste rock piles. Sources and characteristics ore may be released to the land (in disposed air of fugitive emissions dust in mining operations pollution control wastes and spent ore tailings), vary in each case, as do their impacts. Impacts to the air (not removed by air pollution control are difficult to predict and calculate but should devices, or from tailings or heaps), or in the gold be considered since they could be a significant product (i.e., as an impurity). source of hazardous air pollutants. 1.2.2.5 Noise and vibration 1.2.2.4 Incidental releases of mercury associated with mining may Mercury is commonly present in gold ore. include noise from vehicle , loading and Although concentrations vary substantially, even unloading of rock into steel dumpers, chutes, within a specific ore deposit, mercury is found power generation, and other sources. Cumulative in gold ore and associated waste materials. If impacts of shoveling, ripping, drilling, blasting, the content of mercury in a gold ore is 10 mg/ transport, crushing, grinding, and stock-piling can kg, and one million tons of ore is processed at a significantly affect wildlife and nearby residents. particular mine (not unusual concentrations), 10 tons of mercury are potentially released to the Vibrations are associated with many types of environment. This is a major source of mercury equipment used in mining operations, but blasting and should be controlled. is considered the major source. Vibration has affected the stability of infrastructures, buildings, In some projects, gold-containing and homes of people living near large-scale ore is crushed and then, if necessary, heated open-pit mining operations. According to a study and oxidized in roasters or autoclaves to remove commissioned by the European Union in 2000: sulfur and carbonaceous material that affects gold recovery. Mercury that is present in the ore is “Shocks and vibrations as a result of blasting vaporized, particularly in roasters, which are some in connection with mining can lead to noise, of the largest sources of mercury emitted to the dust and collapse of structures in surrounding atmosphere. inhabited areas. The life, on which the local population may depend, might also be Following roasting or autoclaving, the ore is disturbed.”7 mixed with water and reacted with a cyanide leach solution, where gold and mercury are dissolved 1.2.3 Impacts of mining projects and solids removed via filtration. The purified on wildlife solution is sent to an electrowinning process, where the gold is recovered. In this process, Wildlife is a broad term that refers to all plants mercury must also be recovered and collected. If and any animals (or other organisms) that are not not collected by air pollution control devices, this domesticated. Mining affects the environment mercury could be released to the atmosphere and and associated biota through the removal of impact the environment and . vegetation and , the displacement of fauna, the release of pollutants, and the generation of noise. 6 U.S. Environmental Protection Agency, Title 40 Code of Federal Regulations, Section 70.2. http://www.gpo.gov/fdsys/ 7 MINEO Consortium (2000) “Review of potential envi- pkg/CFR-2009-title40-vol15/xml/CFR-2009-title40-vol15- ronmental and social impact of mining” http://www2.brgm.fr/ part70.xml mineo/UserNeed/IMPACTS.pdf

Chapter 1 13 1.2.3.1 Habitat loss example, sediment contamination of rivers and streams is common with . Wildlife species live in communities that depend on each other. Survival of these species can 1.2.3.2 Habitat fragmentation depend on soil conditions, local climate, altitude, and other features of the local habitat. Mining Habitat fragmentation occurs when large areas causes direct and indirect damage to wildlife. The of land are broken up into smaller and smaller impacts stem primarily from disturbing, removing, patches, making dispersal by native species from and redistributing the land surface. Some impacts one patch to another difficult or impossible, and are short-term and confined to the mine site; cutting off migratory routes. Isolation may lead to others may have far-reaching, long-term effects. local decline of species, or genetic effects such as inbreeding. Species that require large patches of The most direct effect on wildlife is destruction or simply disappear. displacement of species in areas of excavation and piling of mine wastes. Mobile wildlife 1.2.4 Impacts of mining projects species, like animals, birds, and predators, on leave these areas. More sedentary animals, like invertebrates, many reptiles, burrowing rodents, Mining can contaminate soils over a large area. and small , may be more severely Agricultural activities near a mining project may affected. be particularly affected. According to a study commissioned by the European Union: If streams, lakes, ponds, or marshes are filled or drained, fish, aquatic invertebrates, and “Mining operations routinely modify the amphibians are severely impacted. supplies surrounding landscape by exposing previously for predators are reduced by the disappearance of undisturbed earthen materials. Erosion of these land and water species. exposed soils, extracted mineral ores, tailings, and fine material in waste rock piles can result Many wildlife species are highly dependent on in substantial sediment loading to surface vegetation growing in natural drainages. This waters and drainage ways. In addition, spills vegetation provides essential food, nesting sites, and leaks of hazardous materials and the and cover for escape from predators. Any activity deposition of contaminated windblown dust that destroys vegetation near ponds, reservoirs, can lead to . marshes, and wetlands reduces the quality and quantity of habitat essential for waterfowl, shore “SOIL CONTAMINATION: Human health birds, and many terrestrial species. and environmental risks from soils generally fall into two categories: (1) contaminated The habitat requirements of many animal species soil resulting from windblown dust, and (2) do not permit them to adjust to changes created soils contaminated from chemical spills and by land disturbance. These changes reduce living residues. Fugitive dust can pose significant space. The degree to which animals tolerate environmental problems at some mines. The human competition for space varies. Some inherent of the dust depends upon species tolerate very little disturbance. In instances the proximity of environmental receptors where a particularly critical habitat is restricted, and type of ore being mined. High levels such as a lake, pond, or primary breeding area, a of arsenic, lead, and radionucleides in species could be eliminated. windblown dust usually pose the greatest risk. Soils contaminated from chemical spills Surface mining can degrade aquatic habitats with and residues at mine sites may pose a direct impacts felt many miles from a mining site. For contact risk when these materials are misused

14 Guidebook for Evaluating Mining Project EIAs as fill materials, ornamental , or “The displacement of settled communities soil supplements.”8 is a significant cause of resentment and conflict associated with large-scale mineral 1.2.5 Impacts of mining projects development. Entire communities may be on social values uprooted and forced to shift elsewhere, often into purpose-built settlements not necessarily of The social impacts of large-scale mining their own choosing. Besides losing their homes, projects are controversial and complex. Mineral communities may also lose their land, and development can create wealth, but it can also thus their livelihoods. Community institutions cause considerable disruption. Mining projects and power relations may also be disrupted. may create jobs, roads, schools, and increase the Displaced communities are often settled in demands of goods and services in remote and areas without adequate resources or are impoverished areas, but the benefits and costs left near the mine, where they may bear the may be unevenly shared. If communities feel brunt of pollution and contamination. Forced they are being unfairly treated or inadequately resettlement can be particularly disastrous compensated, mining projects can lead to social for indigenous communities who have strong tension and violent conflict. cultural and spiritual ties to the of their ancestors and who may find it difficult to 9 EIAs can underestimate or even ignore the impacts survive when these are broken.” of mining projects on local people. Communities feel particularly vulnerable when linkages with 1.2.5.2 Impacts of migration authorities and other sectors of the economy are weak, or when environmental impacts of mining According to the International Institute for (soil, ai, and ) affect the subsistence Environment and Development: and livelihood of local people. “One of the most significant impacts of mining Power differentials can leave a sense of activity is the migration of people into a mine helplessness when communities confront area, particularly in remote parts of developing the potential for change induced by large countries where the mine represents the single and powerful companies. The EIA process most important economic activity. For example, should enforce mechanisms that enable local at the Grasberg mine in Indonesia the local communities to play effective roles in decision- population increased from less than 1000 in making. Mineral activities must ensure that the 1973 to between 100,000 and 110,000 in basic rights of the individual and communities 1999. Similarly, the population of the squatter affected are upheld and not infringed upon. settlements around Porgera in PNG, which These must include the right to control and use opened in 1990, has grown from 4000 to over land; the right to clean water, a safe environment, 18,000.10 This influx of newcomers can have and livelihood; the right to be free from a profound impact on the original inhabitants, intimidation and violence; and the right to be and disputes may arise over land and the fairly compensated for loss. way benefits have been shared. (These were among the factors that led to violent uprisings 1.2.5.1 Human displacement and at Grasberg in the 1970s and the 1990s.) resettlement “Sudden increases in population can also According to the International Institute for lead to pressures on land, water, and other Environment and Development: 9 International Institute for Environment and Development (2002) “Breaking New Ground: Mining, Minerals and Sustain- able Development: Chapter 9: Local Communities and Mines. Breaking New Grounds.” http://www.iied.org/pubs/pdfs/ 8 Ibid. G00901.pdf

Chapter 1 15 resources as well as bringing problems of contamination is transferred to other economic and waste disposal. activities, such as and fishing. The situation is made worse when mining activities “Migration effects may extend far beyond take place in areas inhabited by populations the immediate vicinity of the mine. Improved historically marginalized, discriminated against, or infrastructure can also bring an influx of excluded. settlers. For instance, it is estimated that the 80- meter-wide, 890-kilometre-long Proponents of mining projects must insure that transportation corridor built from the Atlantic the basic rights of affected individuals and to the Carajas mine in Brazil created communities are upheld and not infringed an area of influence of 300,000 square upon. These include rights to control and use kilometres.”10 land, the right to clean water, and the right to livelihood. Such rights may be enshrined in 1.2.5.3 Lost access to clean water national law, based on and expressed through a range of international human rights instruments According to scientists at the University and agreements. All groups are equal under of Manchester (UK) and the University of the law, and the interests of the most vulnerable Colorado(U.S.): groups (low-income and marginalized) need to be identified and protected. “Impacts on water quality and quantity are among the most contentious aspects 1.2.5.5 Impacts on public health of mining projects. Companies insist that the use of modern technologies will EIAs of mining projects often underestimate ensure environmentally friendly mining the potential health risks of mining projects. practices. However, evidence of the negative Hazardous substances and wastes in water, air, environmental impacts of past mining activity and soil can have serious, negative impacts on causes local and downstream populations to public health. The World Health Organization worry that new mining activities will adversely (WHO) defines health as a “state of complete affect their water supply. ... physical, mental and social well-being, and not merely the absence of disease or infirmity.”12 “There are major stakes in these conflicts, affecting everything from local livelihood The term ‘hazardous substances’ is broad and to the solvency of national includes all substances that can be harmful to governments. Fears for water quantity people and/or the environment. Because of the and quality have triggered numerous and quantity, concentration, or physical, chemical or sometimes violent conflicts between miners and infectious characteristics, hazardous substances communities.”11 may (1) cause or contribute to an increase of mortality or an increase in serious irreversible or 1.2.5.4 Impacts on livelihoods incapacitating illness; or (2) pose a substantial present or potential hazard to human health or When mining activities are not adequately the environment when improperly treated, stored, managed, the result is degraded soils, water, transported, disposed of, or otherwise managed. , and forest resources, which are critical to the subsistence of local people. When contamination is not controlled, the cost of the

10 Ibid. 11 Bebbington, A., & Williams, M. (2008) “Water and Mining Conflicts in Peru.” Mountain Research and Develop- 12 World Health Organization. 1946. Preamble to the ment. 28(3/4):190-195 http://snobear.colorado.edu/Markw/ Constitution of the World Health Organization. Official Records Research/08_peru.pdf of the World Health Organization No. 2, p. 100.

16 Guidebook for Evaluating Mining Project EIAs Frequent public health problems related to mining • Visual impacts due to clearing of activities include: vegetation, large excavations, dust, and the presence of large-scale equipment, • Water: Surface and ground water and vehicles. contamination with metals and elements; microbiological contamination from 1.2.6 and wastes in campsites and mine considerations worker residential areas; • Air: Exposure to high concentrations Every EIA for a project that has the potential to of sulfur dioxide, particulate matter, heavy change the global carbon budget should include metals, including lead, mercury and an assessment of a project’s carbon impact. cadmium; and Large-scale mining projects have the potential to alter global carbon in at least the following ways: • Soil: Deposition of toxic elements from

air emissions. Lost CO2 uptake by forests and vegetation that is cleared. Many large-scale mining projects are Mining activities can suddenly affect quality of life proposed in heavily forested areas of tropical and the physical, mental, and social well-being of that are critical for absorbing atmospheric local communities. Improvised mining towns and (CO2) and maintaining a healthy camps often threaten food availability and safety, balance between CO2 emissions and CO2 uptake. increasing the risk of malnourishment. Indirect Some mining projects propose long-term or even effects of mining on public health can include permanent destruction of tropical forests. EIAs for increased incidence of tuberculosis, , mining projects must include a careful accounting chronic , and gastrointestinal diseases. of how any proposed disturbance of tropical forests will alter the carbon budget. The EIA 1.2.5.6 Impacts to cultural and aesthetic should also include an analysis of the potential for resources the host country to lose funding from international consortiums that have and will be established to Mining activities can cause direct and indirect conserve tropical forests. impacts to cultural resources. Direct impacts can result from construction and other mining 2 (e.g., diesel- activities. Indirect impacts can result from soil CO emitted by machines powered heavy vehicles) involved in extracting erosion and increased accessibility to current or and transporting ore. The EIA should include proposed mining sites. Mining projects can affect a quantitative estimate of CO2 emissions from sacred , historical infrastructures, and machines and vehicles that will be needed during natural landmarks. Potential impacts include: the life of the mining project. These estimates can be based on the rate of fuel consumption (typically • Complete destruction of the ) multiplied by a conversion factor that through surface disturbance or excavation; relates units (typically liters or gallons) of fuel that • Degradation or destruction, due is consumed and units (typically metric tons) of to topographic or hydrological pattern CO2 that is emitted. changes, or from soil movement (removal, erosion, sedimentation); CO2 emitted by the processing of ore into metal (for example, by pyro-metallurgical versus • Unauthorized removal of artifacts or hydro-metallurgical techniques). An example is as a result of increased access found in an assessment by CSIRO minerals of to previously inaccessible areas; and Australia which used the Life Cycle Assessment methodology to estimate the life cycle emissions of greenhouse gases from copper and nickel

Chapter 1 17 production, including mining. This assessment electrowinning.13 The bottom line is that metal found that Life Cycle emissions mining generates more than 1 kg of greenhouse from copper and nickel production range from gas for every 1 kg of metal that is produced, and

3.3 kilograms (kg) of CO2 per kg of metal for this does not take into account lost carbon uptake

copper produced by smelting to 16.1 kg of CO2 of cleared forests. per kg of metal for nickel produced by pressure 13 T. E. Norgate and W. J. Rankin (2000) “Life Cycle Assess- acid leaching followed by solvent extraction and ment of Copper and Nickel Production, Published in Proceedings, Minprex 2000, International Conference on Minerals Processing and Extractive , pp133-138. http://www.minerals.csiro. au/sd/CSIRO_Paper_LCA_CuNi.htm

18 Guidebook for Evaluating Mining Project EIAs