The Earth’s

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Environews Focus

The Earth’s

Open WoundsAbandoned and Orphaned Mines

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Open WoundsAbandoned and Orphaned Mines

Some former mine sites are scars on the land: shafts andtunnels may or may not be boarded closed, and piles of

waste rock dot the landscape. Other former sites appearharmless. Perhaps the slurry of ground rock “tailings” andwater that once was waste from a mill pond has dried intoa smooth field. Plants may have obscured or overrun muchof the evidence of mankind’s incursions into the Earth. Butwhether the land still appears raw or has begun to heal,dormant mine sites can be a source of myriad environ-mental hazards.

Some of the hazards are obvious. Old mine openingsmay be partially caved in or mine timbers rotted, present-

sistible to children and thrill seekers. Workings thatunderlie streets and buildings can collapse. Tailings dams,too, can collapse. Acid mine drainage (AMD)—acidifiedrunoff—can contaminate streams, tinting them with thetelltale orange sediment marking high concentrations ofliberated iron.

often come other, less visible elements, including potential-ly toxic cadmium, copper, lead, manganese, zinc, arsenic,and mercury. High winds can carry dust contaminatedwith metals from tailings deposits and waste piles. Evenancient mining activities can release gases that make airunsafe to breathe—methane from coal mines, and carbonmonoxide from so-called hardrock mines, where metals

such as copper, silver, lead, cadmium, and zinc wereextracted. Waters from uranium or phosphate mines cancarry radiation well above normal background levels. “Eachparticular type of material being extracted will have its ownassociated set of . . . potential environmental and healthissues,” says Geoffrey Plumlee, a U.S. Geological Survey(USGS) research geologist.

Who’s responsible for addressing these problems? Formany of these abandoned mines there is no longer a com-pany that can be held responsible for the environmentaldamages they cause. Some of these mines are hundreds ofyears old, and the companies that owned them are longgone. Others closed just a few years ago, but the miningcompany has either gone bankrupt or for other reasonsisn’t taking responsibility for mine cleanup. “It’s not somuch a question of who dropped the ball and who wasbreaking the law,” says USGS scientist Thomas Chapin.“In many cases there were no laws [governing mine wastedisposal] in the 1800s and 1900s, but these [mines] keepgoing and going and can keep polluting for many tens ifnot hundreds of years.” In fact, abandoned Roman minesin Britain continue to discharge acidic waters today, aftersome 2,000 years.

Whether impacts are from a small long-forgotten sluic-ing site or a massive modern heap-leach operation, if themine is abandoned, in the end it is government that shoul-ders the burden—the cleanup is funded, at least in part,

Other hazards are hidden. Along with the freed iron

ing physical hazards. Carelessly sealed openings are irre-

by tax dollars. Although there is no good esti-mate of the cost to clean up abandoned mines,experts agree that in the United States alone theprice tag reads tens of billions of dollars.

Defining the TermsIn the United States, mines that have beendeserted and are no longer being maintained,and in which further mining is not intended,are called “abandoned” mines. Abandonedmines for which no owner or responsibleparty can be found are called “orphaned”mines. Outside the United States, the mean-ings of these terms are often reversed. For thepurposes of this article, all mines that areclosed and for any reason no company is tak-ing responsibility are called “abandoned.”

Sometimes the term “inactive” is used formines that aren’t currently being mined, butfor which a known owner is still paying taxes.These mines may be reopened if the com-modity can be produced at a profit; minesthat have been abandoned or closed wouldnot fall into this category.

Abandoned mines may be on propertythat is now owned by a third party withoutthe resources to clean up contaminationfound there. In the western UnitedStates, abandoned mines on publicland become the responsibility ofthe federal or state government. Butfor those on privately ownedland—the dominant scenario in theEast—the present owner, whomeverthat might be, retains at least someresponsibility under the CleanWater Act, though this has not gen-erally been enforced, according toArthur Rose, a professor emeritus ofgeochemistry at Pennsylvania StateUniversity. “Basically,” he says, “if itis abandoned, nobody has clearresponsibility.”

The inconsistency of terms isone of the many problems in esti-mating the number of abandonedand orphaned mines around theworld. Another is the discrepancybetween what different organizationsinclude in their counts of mines.“There are a lot of what people call‘dog holes’ that are small exploration[prospects] that are all over theplace,” says Kathleen Smith, a USGSgeochemist in Denver. These smallprospects were created by individualsprior to the advent of drilling toexplore for mineral deposits.Prospects were never mines; theywere early one-man, short-termoperations. Other so-called discov-ery pits, dug largely as a formalityunder regulations for staking a min-ing claim on federal land, are typi-

cally about six feet deep and commonly dis-close little or no valuable minerals, says Rose.

According to Stanley E. Church, a USGSresearch geologist and abandoned mine landsproject chief, prospects may pose some of thesame hazards as mines. He explains that “wet”prospects—those that intersect groundwa-ter—may present a possible AMD problem,although the workings of any one prospect areoften so small that individual sites do not con-tribute large amounts of contaminated water.“Dry” prospects pose mostly physical hazards.Discovery pits are largely innocuous, saysRose.

Church says that many of the holes in theground cited in various estimates are indeedjust prospects and discovery pits. “The USGSMineral Resources Data System would indi-cate that there are about 35,000 metal minesin the United States; that is, a hole in theground from which there is a public record ofmetal production,” he says.

This is in stark contrast to an estimatepublished in the 1993 report The Burden ofGilt by the Mineral Policy Center—aWashington, D.C., environmental organiza-tion—that there are as many as 557,650

abandoned mines in the United States alone.The National Park Service estimates thatthere are 4,000 abandoned mines on U.S.national parklands, and the Forest Serviceestimates 25,000 on land it manages. Thereis no way of knowing which of these are trulymines and which are prospects.

The same is true of estimates from othercountries. According to the April 2002 draftreport Mining for the Future, compiled by theInternational Institute for Environment andDevelopment, the number of abandonedmines in Canada is estimated at about10,000, and South Africa has 134 abandonedasbestos mines and 400 asbestos mine dumpsthat supply a steady flow of asbestos dust tothe region. In the 2000 United NationsEnvironment Programme report Mining andSustainable Development II: Challenges andPerspectives, Sweden is listed as having morethan 1,000 abandoned mines, and a nationalsurvey of Japan found 5,500 abandonedmines. A study presented at a March 2000workshop organized by the World Bank andthe Metal Mining Agency of Japan foundthat over 300 Chilean tailings storage facili-ties had been abandoned with no attempt to

clean up the sites. In many other countries, no

comprehensive survey of abandonedmines has been attempted. And evenin areas that have been surveyed,many old mines are undocumented.All in all, worldwide, it is likely thatthere are millions of abandonedmines, according to the WorldBusiness Council for SustainableDevelopment.

Still, says Rose, “Giving num-bers of abandoned ‘mines’ is prettymeaningless—we need good evalua-tion of individual sites.” The impor-tant conclusion, says Church, is thatat only a small number of these siteswill there likely be companies withresources to clean them up.

In practical terms, says U.S.Environmental Protection Agency(EPA) biologist and geologist CarolRussell, whether there are 100,000 or500,000 abandoned mines may notmatter much. “There are so manythat we don’t need to go inventorythem,” she says. “We don’t haveenough money to deal with the oneswe’ve found already.”

AMD: The Chief ProblemBy far the most persistent and dam-aging environmental effect fromabandoned mines—both hardrockand coal—is AMD. (This is in con-trast to acidity that is produced as aresult of weathering of mineralized

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Acid burn. AMD seeps from St. Kevin Gulch near Leadville, Colorado,an area mined for gold, silver, lead, and zinc.

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rock that has not been mined, called “acidrock drainage” by the mining industry.) Inshort, AMD is acidic water, in the worst casesso acidic as to dissolve metal tools. In fact, themost acidic water in the world is found inunderground mine workings at the IronMountain mine in northern California,according to research published in the 30March 1999 issue of Proceedings of theNational Academy of Sciences by D. KirkNordstrom and Charles Alpers, both USGSresearch chemists. The water there has a pHof –3.6. For comparison, on the logarithmicpH scale, pure water is neutral at pH 7.0,lemon juice is pH 2.4, and a 30% sulfuricacid solution, such as battery acid, is pH –2.0.

Acid drainage occurs when water, air, cer-tain bacteria, and sulfide metals(such as pyrite, marcasite, and chal-copyrite) come into contact witheach other. When it forms natural-ly, acid drainage can produce thetelltale “red water” that was one ofthe first signposts that early minersused to find mineral deposits.Natural weathering usually doesn’tproduce enough acidity to signifi-cantly impact the environment.That’s because not enough sulfidesare at the surface, where they canbe exposed to air and water. Butthere are exceptions, says Church.Some creeks in Colorado, forexample, are naturally too acidic tosupport most forms of aquatic life.“A fairly substantial component ofthe acidity in some streams is relat-ed simply to natural weatheringprocesses and has nothing to do with min-ing,” he explains. Furthermore, summer rain-fall events can cause a pulse of acidity andmetals into the streams that may cause deathof aquatic life in watersheds whether or notthey have been affected by historical mining.

Mining, however, can bring large quanti-ties of sulfides to the surface and break theminto small pieces, thus exposing more surfacearea to react with air and water, producingAMD. Sulfides tend to appear in the samegeologic conditions as many types of minedmetals and coals. “When you bring this ironsulfide to the surface, what you’re doing isexposing these metal sulfides to oxygen andwater,” Chapin says. The oxidation of the sul-fides creates a lot of acidity. The resulting sul-furic acid serves as a medium in which spe-cialized microbes flourish. These microbes inturn further oxidize the minerals. The result isa chain reaction that will continue until thesulfides are consumed. Depending on themineral deposit, that process can take hun-dreds to thousands of years.

The speed and duration of this acid-pro-ducing reaction is one of the differences

between coal mines and hardrock mines,explains Paul Ziemkiewicz, director of theWest Virginia Water Research Institute atWest Virginia University. “The maximumacid production that you’re going to get out ofa [coal] mine is going to be in the first tenyears or so. After that you start expendingyour pyrite,” he says. In coal deposits, the sur-rounding rock typically contains 2–5% sul-fides, most of which is pyrite. “The highestwe ever get might be twelve percent pyrite,and that would be extremely high,” saysZiemkiewicz.

Conversely, hardrock mine waste rock,tailings, displaced surface material (“overbur-den”), and other rock surrounding an aban-doned hardrock mine can contain up to 50%

sulfides, Ziemkiewicz says. Most AMD flowsfrom the mines themselves. Not only do somehardrock mine wastes contain high amountsof pyrite, there is proportionally more minewaste at individual sites than in coal mines. Acoal mine isn’t worth working unless most ofwhat is pulled from the ground is coal. In coalmines, ore that comes out of ground is83–85% product, Ziemkiewicz says. In thehardrock world, often less than 1% of therock brought to the surface is actually used.For gold mines, the actual metal extracted canbe just a fraction of a percent, with minersworking deposits that contain as little as0.015 ounces of gold per ton of rock. Thismeans that, for some gold deposits, massiveamounts of high-sulfide-content rock may beextracted, and the result would be an enor-mous supply of sulfide that is available foracid generation, which can continue to react,releasing acid indefinitely.

Another mitigating factor for acid pro-duction from coal mines, Ziemkiewicz says, isthe alkaline minerals often found among coaldeposits. “A lot of the spoils around a coalmine can contain limestone,” he says. Such

materials neutralize acid to at least someextent but are less commonly found inhardrock mines. (However, says Church, forthe large gold deposits currently being minedin the Carlin trend in Nevada, many are host-ed in carbonate rock, and the water fromthem is alkaline rather than acidic.)

Finally, the types of sulfides most oftenfound in coal mines may be more reactivethan the types found in hardrock mines. Afterjust six weeks above ground, a pile of coalmine waste can have pH 2.4 (very acidic)water draining from it, Ziemkiewicz says. Athardrock mine sites, it can take several yearsbefore significant quantities of acidic waterstart to flow. In geologic terms, where “fast”can mean thousands of years, coal mine

AMD is a flash flood compared tohardrock’s creek that matures intoa river.

Why does that matter? In anaverage coal mine, Ziemkiewiczsays, the sulfides are consumed ata rate of about 2% per year. “Thatmeans in thirty years you’d havehalf the acid drainage that you[started with].” But for manyhardrock mines, there is no end insight within our lifetimes becauseof the large volumes of pyritepresent. These differences affectremediation strategies and couldhave implications for policy mak-ers as well, he says.

The acidity itself can suppressthe life in waterways and ifallowed to build up in standingwater, such as pit lakes, can kill

larger animals such as caribou, moose, andmigrating waterfowl, according to Solutions toAcid Mine Drainage, a fact sheet published byNatural Resources Canada. But more signifi-cant are the metals that the acid releases.Traces of unwanted metals are almost alwayscoexistent in deposits of the target metal,whatever that might be. A whole suite ofpotential toxicants—such as arsenic, lead,cadmium, mercury, zinc, iron, copper, alu-minum, and manganese—can be found inhardrock mines. Coal mines tend to be morebenign, with manganese, iron, and aluminumthe primary metals found in the AMD fromthese sites, although other metals such as zinccan also be present.

As the sulfides break down, these ele-ments are released. The acid releases the ele-ments, and the very acidity also keeps themin soluble form. Toxicants that are liberatedand transported by AMD can contaminateentire watersheds, including drinking watersupplies. In Lodge Pole, Montana, for exam-ple, the Zortman-Landusky gold mine—abandoned since 1998, when the PegasusGold Corporation declared bankruptcy—Pa

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Closed but no closure. The bulldozed Treharris coal mine in southernWales remains an eyesore and potential hazard to the residents nearby.

sends variable amounts of lead, arsenic, andcadmium into the streams and groundwaterthat supply drinking water for the region’scommunities.

Historically, the structure of many oldermines accelerated the rates of developmentand delivery of AMD into affected water-sheds, says Plumlee. “In many mines, espe-cially back in the late 1800s and on throughthe first half of the 1900s, the minerals thatthey were interested in mining occurredbelow the water table,” he explains. “If themine workings were on a hill, they woulddrive a horizontal tunnel [called an “adit”] atthe base of the hill beneath the mine work-ings and let the tunnel drain all of thegroundwater. Those tunnels are continuingto serve their original purpose in drainingthe mined area, and they are significantpoint sources of acid and metals in manydistricts.”

At some mine sites, attempts to plug thesetunnels just made the problem worse. Thepooled water builds up and then forces its wayout through many smaller openings, occasion-ally thousands of feet from the tunnel

entrance. Following plugging, however, manymine tunnels can be reduced to a minor envi-ronmental problem, says Church.

An especially damaging scenario,although fortunately quite a rare occurrence,says Plumlee, is when an open pit mine isbuilt over what had been an undergroundmine. Russell says that’s what happened at theformer gold mine in Summitville, Colorado,a Superfund site at which the government hasalready spent about $155 million. Summit-ville was developed from underground work-ings in the 1800s, and a drainage tunnel wasinstalled in 1903. But from 1985 until 1992it was operated as an open pit mine. The pitcaught rain and snowmelt, and funneled itdown into fractures and the undergroundworkings, from which it drained through anadit. Plugging the adit in 1994 helped reduceloadings of acid and metals from the site, buta number of seeps of acid water developedafter the plugging. Now the plug is being usedas a flow regulator and the undergroundworkings as a temporary storage, so that amanageable volume of acid waters can betreated during high-flow conditions following

snowmelt. “Summitville . . . was a geologicand climatologic recipe for extreme acid minedrainage,” Plumlee says. The drainage fromSummitville polluted the local watershed withsignificant quantities of acid water rich insuch elements as arsenic, iron, copper, alu-minum, and zinc. Although remediationefforts have substantially decreased theamounts of acid and metals leaving the site,says Plumlee, long-term water treatment willbe needed.

Inadequate engineering and planning forAMD during mine site planning and develop-ment often worsens the impact of abandonedmines on the environment, says Joan Kuyek,national coordinator of the environmentalorganization MiningWatch Canada. In north-ern Canada, shifts in climate are putting atwist on the problem of AMD. “A lot of our[northern] mines are built into permafrostand depend on permafrost to hold the tailingsin place,” she says; unlike dry southern cli-mates such as Nevada, where tailings eventu-ally dry out, in the frozen north they areexpected to stay frozen. Structures such asmine walls and tailings dams are stable as long

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Scar tissue. A crisscross of roads and pits scars the surface of a former gold mine in Summitville, Colorado, while underground workings and tunnels allowacidic waste to drain into nearby watersheds. The Superfund site has cost more than $150 million in remediation efforts and remains incomplete.

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as the permafrost doesn’t thaw. But if they andthe dam containing them thaw, a slurry ofground rock, metals, and the chemicals usedto process them can flood waterways. Andwater that is no longer immobile can now pro-vide the once-missing component for AMDreactions in sulfide-rich deposits.

Changes in climate—many studies sug-gest a 2–4°C warming of North Slope per-mafrost—are bringing problems with thisscenario, Kuyek says. “We’re finding thatsome of these dams are collapsing. A lot ofrivers and streams are in areas where FirstNations peoples depend on them for a liv-ing, and they are discovering that minesupstream are contaminating the water.”

Dirk van Zyl, a professor of mining engi-neering and director of the Mining Life-Cycle Center at the University of Nevada’sMackay School of Mines, estimates thatabout 5% of abandoned mines cause somekind of environmental damage. Mining pol-lution affects about 40% of watersheds in thewestern United States, according to the EPA’s2002 Toxics Release Inventory. In theAppalachians, acid mine drainage hasdegraded more than 8,000 miles of streams,leaving some aquatic habitats virtually life-less, according to the April 1998 USGS pam-phlet Biology in Focus: Better Lives ThroughBetter Science: New Hope for Acid Streams.Trout streams throughout Pennsylvania andOhio have become too acidic for troutbecause of runoff from abandoned coalmines, says Ziemkiewicz. In California’sSierra Nevada range, mercury from aban-doned hydraulic gold mines active in the late19th century has accumulated in fish, mak-ing them unsuitable for eating.

In a Colorado stretch of the RockyMountains, rain passing through waste rockand ore tailings at closed metal mines maybe poisoning a type of grouse called thewhite-tailed ptarmigan. In the 13 July 2000issue of Nature, Cornell ecologist JamesLarison and colleagues report finding elevat-ed liver and kidney cadmium concentrationsin all the older ptarmigan they examined,and high mortality among adult cadmium-contaminated females. They theorize thatthe females of the species are particularlyaffected because they overwinter at lowerelevations than the males, in areas that tendto be downstream of abandoned mines.Cadmium, which is readily mobilized bymining, is swept downstream in waterwaysthat feed the willow trees that are a large partof the ptarmigan diet. These willows bioac-cumulate cadmium in their buds by twoorders of magnitude, according to Larison.The high concentrations of cadmium weak-en the birds’ bones and damage their kid-neys. Other birds as well as regional mam-mals may also be at risk, the researchers say.

Other Environmental HazardsMany of the same issues apply to both coalmining and hardrock mining. Most obviousof the hazards that abandoned mines pose arethe physical ones. Adventurers and childrencan’t resist the lure of an open, partially col-lapsed, or carelessly sealed mine shaft. Butmines can be unstable. They are littered withloose rock and rotten ladders and supporttimbers. Walls can give way. Water—some ofit acidic enough to cause chemical burns—can pool in unexpected places.

Mine shafts and tunnels can cause prob-lems far from the mine opening as well. Incoal mines especially, since they are workedcloser to the surface than hardrock mines,mine workings can collapse, engulfing vehi-cles, buildings, and people. In coal country,such as Ohio, West Virginia, andPennsylvania, it’s not unusual for sinkholes todevelop under new construction projects andon occasion existing structures as well, says

Ann Harris, a geology professor atYoungstown State University who maps for-gotten 100-year-old coal mines in Ohio.

Stored waste is another problem. Someabandoned Canadian mines are struggling toremedy the way arsenic trioxide—a by-prod-uct of the roasting method used to extractgold from rock—was disposed of. In thismethod, finely ground ore was heated to burnoff organic matter and release sulfur dioxidefrom the sulfides. Then it was mixed withchloride of lime and sulfuric acid in revolvingwooden barrels to dissolve the gold. This solu-tion was then passed through charcoal beds,which resulted in the gold adhering to the

charcoal’s surface. Finally, the charcoal wasincinerated, leaving behind molten gold thatwas formed into ingots.

“We’ve got 237,000 tons of arsenic triox-ide stored in underground mine tunnels inYellowknife [Northwest Territories], andnobody knows what to do about it,” Kuyeksays (some government documents put thisfigure at 270,000 tons). “In the old days theyused to get the gold out of arsenic-bearingore by roasting it. Then they would blow thearsenic trioxide into the tunnels to store it.”Although leaching through fractures intoGreat Slave Lake is minimal at this time, with-out containment it could become worse,Kuyek says.

When the Giant mine—the source of thisarsenic—closed in 1999, it was the last gold-roasting operation in Canada. During the firstthree years that it was in business, starting in1948, as much as 7,000 kilograms of arsenictrioxide per day was emitted from its smoke-stacks and blown by the wind across the coun-tryside. In 1951, the mine operators startedcapturing most of the arsenic trioxide anddepositing it, although about 25 kilogramscontinued to escape each day.

Other contaminants plague other sites.Libby, Montana, is the site of a closed vermic-ulite mine that is contaminated with asbestos.Researchers have found high concentrationsof asbestos in household dust, yard soil, andelsewhere throughout the town. The humandeath rate there from asbestosis was 40–80times higher than expected, and lung cancermortality was 1.2–1.3 times higher thanexpected when compared to Montana and theUnited States overall, according to a 2002report by the U.S. Agency for ToxicSubstances and Disease Registry titledMortality in Libby, Montana (1979–1998).

Also associated with gold mining is mer-cury, a toxic remnant of the U.S. andCanadian gold rushes of the mid to late 19thcentury and the Amazon gold rush of the late20th century. Amalgamation with mercury isone of the oldest chemical methods for sepa-rating particles of gold from other materials.(Modern large-scale operations use cyanide.)Gravel and mud, collected through dredgingor blown free with water cannons, passedthrough sluices over a copper plate coatedwith mercury. The gold combined with themercury, and the resulting amalgam wasboiled to vaporize the mercury, which wascaptured in a retort. Although mercury, beingquite expensive, was most often captured andreused, some invariably found its way into theenvironment.

In California’s Sierra Nevada range, forexample, hundreds to thousands of pounds ofmercury may remain at each of the region’shundreds of gold mines, says Alpers [see“Tarnishing the Earth: Gold Mining’s DirtyBL

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Lying in wait. Old mines present structuralhazards such as the danger of collapse or acci-dental falls.

Secret,” EHP 109:A474–A481]. In the envi-ronment, mercury is transformed by bacteriainto the more toxic methylmercury form, andthen bioaccumulates up the food chainthrough invertebrates to amphibians, fish, andfish-eaters such as birds and humans. At highlevels, methylmercury has been linked totremors, paralysis, anemia, bone deformities,and death. Research published by PhilippeGrandjean of Odense University and col-leagues in the July 1999 issue of EHP demon-strated that mercury poisoning that can betraced to the Amazonian gold mining boomhas decreased the performance of indigenouschildren on a battery of cognitive tests of visu-al spatial function and memory.

But even mercury in its elemental formcan prove hazardous, at least to amateur treas-ure hunters, who often pan for gold in aban-doned sluice tunnels left over from the goldrush. Panning in tunnels is dangerous becauseit can stir up mercury vapors in a relativelyenclosed area. But the greater risk—to indi-viduals and to the public at large—is whathappens to the gold–mercury amalgam“treasure” at home. People would either roastit, Alpers says, releasing dangerous fumes andallowing mercury to escape into the environ-ment, or they would treat it with nitric acid.“That mercuric nitrate solution might getdisposed of inappropriately,” Alpers says.“Someone may just flush that down the toiletor throw it out in the backyard, and thenyou’ve got mercury in a very bioavailableform, more so than it was to begin with. Oneflush from somebody’s gold panning opera-tion could [put] more mercury [in the envi-ronment] than the whole city of Sacramento[releases in] a year.” In the summer of 2000,the EPA spent about $1.4 million to clean upa tunnel of the Polar Star mine in Californiawhere people had panned for gold nuggets,Alpers says. Cleaning up just that one tunnelcost U.S. taxpayers about $3,000 per linearfoot, he says, “and there are dozens, if nothundreds, of other tunnels out there, many ofthem thousands of feet long.”

The Cost of CleanupAMD cleanup can be expensive and lengthy,and, if the AMD isn’t halted, must be main-tained indefinitely. Preventing AMD in thefirst place is vastly preferable to cleaning it upafter the fact, and progress is being made inprevention technologies [see “Tarnishing theEarth: Gold Mining’s Dirty Secret”]. But forsites where prevention is no longer anoption, good methods for “passive” remedia-tion of acid drainage have been developedusing wetlands and reaction with limestoneto neutralize the acid and eliminate the met-als, says Rose. Such methods are now beingused to eliminate AMD from many aban-doned coal mines and some abandoned

metal mines. States such as Pennsylvania arefunding numerous volunteer watershedgroups to survey for abandoned mine sites,design treatment, and pay for constructionof passive systems.

Because there are so many unknown fac-tors, estimates of the cost to clean up aban-doned mines in the United States vary wide-ly. The number of abandoned mines isn’tknown for sure, development of cost-effectiveremediation methods is still a work inprogress, the extent of environmental impactsis often unexamined, and in many cases itappears as though treatment may have to con-tinue indefinitely. The Burden of Gilt pegs theamount of money required to remediate U.S.mines at $32.7–71.5 billion.

In Canada, calculating cleanup is just asuncertain. A 1999 report by the CanadianInstitute for Environmental Law and Policy,titled Mining’s Many Faces: The Environ-mental Mining Law and Policy in Canada,puts the cost to clean up Ontario’s morethan 5,000 abandoned mines at Can$3 bil-lion. A 2000 report by MiningWatchCanada and the Pembina Institute forAppropriate Development (an independentresearch entity) said that the cost inOntario would be Can$300–400 million.The same report also estimated Can$639.5million as the public liability for cleaningup mines in the Northwest Territories andYukon, more than Can$85 million inBritish Columbia, and Can$75–350 mil-

lion in Québec. But the 2002 Report of theCommissioner of the Environment andSustainable Development by the Office of theAuditor General of Canada sets the costs toclean up “abandoned mines in the North,”which includes the Northwest Territories,Yukon, and Nunavut, at Can$555 million.In 2002 alone, Indian and Northern AffairsCanada spent Can$26 million to addresswater contamination from abandonedmines in these areas.

More concrete are figures for minecleanups that have been completed or are inprogress. Mining in Butte, Montana, startedin 1864, has deposited tons of cadmium,arsenic, copper and other toxicants in the120-mile-long Clark Fork River. Much ofthis mine waste accumulates at the MilltownDam, which is about 5 miles upstream ofMissoula. Milltown Dam is one of the mostexpensive Superfund sites. So far, more than$700 million has been spent cleaning up thesite, and projections tag the cost to completethe project at as much as another $100 mil-lion over the next 12 years. Of the 1,234industrial sites on the Superfund NationalPriorities List dated 24 October 2002, about25 are mines—some of which are active.

When a company abandons a mine sitebut stays in business, lawsuits can bebrought by government agencies, individu-als, and nonprofit groups to remediate theenvironmental damage. In California in2000, Aventis Crop Sciences USA, then a

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A mountain of problems. The Iron Mountain mine site in Shasta County, California (left), once asite of gold, copper, and zinc mining, encompasses 4,400 acres. The Minnesota Flats treatmentplant (right top) was built in 1994 to treat AMD from the site. Drainage from the site’s Richmondmine collects in a pool (right bottom).

division of European giant Aventis SA,agreed to pay $160 million down for aninsurance policy that will pay up to $300million in cleanup costs over the next 30years if it is needed, plus a final $514 millionpayment in 2030. These funds will be usedto remediate the closed Iron Mountain minein Redding, California. This was in additionto more than $200 million spent by thecompany and the U.S. EPA on site charac-terization, remediation, and water treatmentprior to 2000. The copper mine closed in1963, yet, according to a 19 October 2000EPA press release, “Prior to the actionrequired by the U.S. EPA and the state, themountain discharged approximately a ton ofcopper and zinc each day—equal to approx-imately one-quarter of the total national dis-charge of copper and zinc to surface watersfrom industrial and municipal pointsources.”

For mines whose owners are long for-gotten, however, the role of addressingcleanup invariably falls to governmentalagencies, generally to the federal land man-agement agencies. In some cases, the actualcosts are covered by special funds to whichthe mining industry contributes. In theUnited States, the U.S. Surface MiningControl and Reclamation Act of 1977(SMCRA) requires that the Office ofSurface Mining collect funds to pay for therestoration of coal mines that closed before3 August 1977. Coal mining companies

must pay 35¢ per ton for surface-minedcoal, 15¢ per ton for coal from undergroundmines, and 10¢ per ton for lignite, which isa moist brown or yellow intermediatebetween coal and peat. The AbandonedMine Reclamation Fund, administered bythe Office of Surface Mining, manages thismoney, half of which is returned to SMCRAstates for cleanup purposes. State abandonedmine land projects are free to use this moneyto remediate any abandoned coal mine. Andif all of the state’s coal mines have beenrestored, the funds can be used to remediatehardrock mines. According to several min-ing experts, much of this funding—as muchas $1.5 billion—is tied up in congressionaland administration politics. Thus, coal com-panies are paying into the fund, but a gooddeal of the money is not being used forcleanup of abandoned mines.

Furthermore, only states in which coal ismined qualify to collect these funds. Thewestern states of New Mexico, Colorado,Wyoming, Montana, Utah, and Washingtonreceive SMCRA funds, whereas Arizona,Nevada, Idaho, Oregon, and California donot. This leaves the latter states, which are lit-tered with abandoned hardrock mines, out inthe cold. With the exception of theSuperfund program and small line items inthe budgets of the Bureau of LandManagement and the Forest Service ($10million and $15 million, respectively, for fis-cal year 2002), no other federal source of

remediation funds is inplace.

And even organiza-tions in states that doreceive SMCRA fundshave objections to thecurrent system. Funds aredistributed in proportionto current levels of coalmining in each state. Butcurrent mining levels don’tnecessarily reflect theamount of reclamationneeded in each state, argueenvironmental groups suchas the Pennsylvania Organ-ization for Watersheds andRivers. Wyoming, forexample, is producing coaland—under the currentformula—is projected toreceive about $21.3 mil-lion in 2003, but has rela-tively few unremediatedabandoned coal mines onwhich to spend thatmoney, and few aban-doned hardrock mines.Pennsylvania, where coalmining has tapered off

over the years, will receive $19.7 million, buthas abandoned coal mines that will cost anestimated $4.5 billion to remediate. AndWest Virginia, another historic coal mininghotbed, will receive about $17.5 million butneeds about $625 million to reclaim itsmines. “It is essentially unfair,” says AlanSeptoff, research and information systemsdirector of the Mineral Policy Center.“Hardrock mining should pay its own freightwhen it comes to abandoned mine cleanup.”

SMCRA expires in 2004, and severaleastern environmental organizations havesuggested that if the act is extended—by nomeans a sure thing—a new formula for dis-tributing monies based on need rather thanon production should be developed.

There have been proposals to providesimilar funds to reclaim hardrock mines. On21 March 2002, Mark Udall (D–Colorado)introduced H.R. 4078, the AbandonedHardrock Mines Reclamation Act of 2002.The billed stalled in committee but is expect-ed to be reintroduced in 2003. An alternativebill expected to be introduced will proposethat the Animas River watershed in Coloradobe designated a watershed for pilot remedia-tion projects. Among other provisions, thebill would have required the owners ofhardrock mines that gross more than$500,000 a year to pay into a Department ofInterior fund. Like the SMCRA fund, thismoney would be used for remediation proj-ects at hardrock mine sites. The bill alsowould have made it possible for “goodSamaritans,” typically local citizens’ groups,to clean up abandoned mines without assum-ing legal liability for preexisting pollution.Even if the new bill is passed, it is projected tocollect only $40 million per year, a fraction ofthe cost of addressing a single large mine.

Other proposals have been made at thestate level. In January 1999 the Idaho MiningAssociation proposed that one-third of Idahomine license tax monies go to the state’s aban-doned mine reclamation account (a programseparate from the state’s abandoned mine landprogram). The mine license tax, which isimposed on the net value of ore mined inIdaho, collected only $4.8 million over 10years ending in 1998.

Although there is plenty of controversyover abandoned mines, experts agree on atleast a few major points: the scope of theimpacts of abandoned mines isn’t well under-stood, the damage that untended minescause is increasing, and adequate funds aren’tavailable to address even the largest, mostharmful mine sites. And although scientistsare developing new methods to treat aban-doned mines, the field of mine remediationis still in its infancy.

Scott Fields

Environmental Health Perspectives • VOLUME 111 | NUMBER 3 | March 2003 A 161

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Focus | The Earth’s Open Wounds