Mitigating the Toxic Remnants of the Berkeley Pit Mine

The Berke­ley Pit in Butte, Mon­tana is a for­mer open-pit cop­per mine that has tran­si­tioned from an engine of eco­nom­ic pros­per­i­ty to a site of envi­ron­men­tal and human­i­tar­i­an con­cern due to its trans­for­ma­tion into a tox­ic lake fol­low­ing the clo­sure of min­ing oper­a­tions. The Berke­ley Pit illus­trates the press­ing need for sus­tain­able min­ing prac­tices and robust post-min­ing strate­gies to address envi­ron­men­tal degra­da­tion and pol­lu­tant expo­sure to local communities.
At its peak, But­te’s rich­ness in cop­per led to its nick­name “The Rich­est Hill on Earth,” with the Berke­ley Pit as one of the largest truck-oper­at­ed open-pit cop­per mines in the Unit­ed States. Oper­a­tions at the pit, which began in 1955 and con­tin­ued until 1982, exca­vat­ed an immense cav­i­ty stretch­ing over 1.5 miles long, 1 mile wide, and 1,600 feet deep. The wealth drawn from the pit fueled the econ­o­my but at grave envi­ron­men­tal and health costs to the sur­round­ing ecosys­tem and community.
Upon ter­mi­na­tion of min­ing, dewa­ter­ing pumps were switched off, lead­ing to the grad­ual accu­mu­la­tion of water in the pit. Rain­fall and ground­wa­ter inflow result­ed in a tox­ic lake with dan­ger­ous­ly high con­cen­tra­tions of heavy met­als like arsenic, cad­mi­um, zinc, and sul­fu­ric acid, among oth­er con­t­a­m­i­nants. As of 2023, the Berke­ley Pit water lev­el had reached over 900 feet deep, pos­ing a threat to the sur­round­ing ground­wa­ter and the ecosys­tems of Butte, Mon­tana. 30 bil­lion gal­lons of acidic water inhib­it nat­ur­al flo­ra and fau­na from thriv­ing, high­light­ing severe eco­log­i­cal impacts. Migra­to­ry bird deaths in the thou­sands have been record­ed over the years as they land on the decep­tive­ly invit­ing, yet high­ly acidic and met­al-laden lake.
The health effects on res­i­dents sur­round­ing the Berke­ley Pit are of sig­nif­i­cant con­cern and take both a phys­i­o­log­i­cal and psy­cho­log­i­cal toll on the com­mu­ni­ty. Long-term expo­sure to heavy met­als and oth­er tox­ic sub­stances com­mon­ly asso­ci­at­ed with the Pit can lead to seri­ous health issues, includ­ing res­pi­ra­to­ry prob­lems, skin dis­or­ders, and an increased risk of can­cers, such as lung and kid­ney can­cer due to arsenic and sil­i­ca par­tic­u­late expo­sure. More­over, chil­dren are par­tic­u­lar­ly vul­ner­a­ble, with poten­tial devel­op­men­tal delays and cog­ni­tive impair­ments linked to lead expo­sure. Men­tal health is also impact­ed as res­i­dents live with the stress and anx­i­ety of poten­tial health risks and envi­ron­men­tal degra­da­tion of their hometown.
The Envi­ron­men­tal Pro­tec­tion Agency (EPA) has played a crit­i­cal role in address­ing the cleanup of haz­ardous con­di­tions at the Berke­ley Pit and its sur­round­ings. For five years the site was aban­doned and unmit­i­gat­ed until it became the largest site of the EPA’s Super­fund pro­gram in 1987, which rec­og­nized and mobi­lized cleanup efforts for some of the nation’s most con­t­a­m­i­nat­ed lands. To mit­i­gate the impact of the tox­ic waters, the EPA has devel­oped a mul­ti-faceted reme­di­al plan in col­lab­o­ra­tion with the state of Mon­tana, local offi­cials, and Atlantic Rich­field Com­pa­ny (ARCO), which inher­it­ed the lia­bil­i­ties of Ana­con­da Cop­per, the com­pa­ny orig­i­nal­ly respon­si­ble for the mine. A key com­po­nent of the cleanup strat­e­gy is main­tain­ing water lev­els below a crit­i­cal point to ensure con­t­a­m­i­nat­ed water does not over­flow into the local ground­wa­ter sys­tem. To accom­plish this, the EPA con­struct­ed the Horse­shoe Bend Water Treat­ment Plant, which can treat 7 mil­lion gal­lons of water a day pumped from the Berke­ley Pit and sur­round­ing mines. The plant removes heavy met­als and neu­tral­izes acid­i­ty before the water enters the near­by Sil­ver Bow Creek or the Clark Fork Riv­er. Addi­tion­al­ly, stormwa­ter chan­nels have been built to direct water from the min­ing site direct­ly into the Berke­ly Pit to reduce con­t­a­m­i­nat­ed runoff reach­ing the ground­wa­ter. In total, the water treat­ment oper­a­tion is a cor­ner­stone of the region’s envi­ron­men­tal man­age­ment plan and has undoubt­ed­ly saved the cit­i­zens of Butte, Mon­tana from fur­ther expo­sure to the tox­ic remains of the open pit mine. How­ev­er, this reme­di­a­tion strat­e­gy needs to be con­stant­ly mon­i­tored and main­tained. The Berke­ley Pit is cur­rent­ly fed­er­al­ly man­dat­ed to be main­tained for­ev­er, but a dras­tic change in pol­i­cy or EPA fund­ing could result in dis­as­ter for the res­i­dents and envi­ron­ment of Butte.
The Berke­ley Pit case study serves as a cau­tion­ary tale of the endur­ing envi­ron­men­tal and human­i­tar­i­an impacts min­ing oper­a­tions can have post-oper­a­tion. Due to the absence of respon­si­ble mine man­age­ment and com­pre­hen­sive envi­ron­men­tal leg­is­la­tion, the res­i­dents of Butte, Mon­tana will for­ev­er have the threat of a tox­ic pit loom­ing over the health of their com­mu­ni­ty. Look­ing to the future, pro­pos­als such as stricter clo­sure pro­ce­dures for mines, con­tin­u­ous mon­i­tor­ing of envi­ron­men­tal con­di­tions, and ade­quate finan­cial assur­ance for post-min­ing clean-up activ­i­ties could all con­tribute to mit­i­gat­ing and pre­vent­ing long-term envi­ron­men­tal and human­i­tar­i­an impacts caused by sites such as the Berke­ley Pit.

1. How can the min­ing indus­try be held more account­able for the long-term envi­ron­men­tal and health con­se­quences of their oper­a­tions, and what reg­u­la­to­ry frame­works or finan­cial mech­a­nisms could be estab­lished to ensure that min­ing com­pa­nies bear the respon­si­bil­i­ty for cleanup and health­care costs asso­ci­at­ed with their activities?

2. In the case of the Berke­ley Pit, where the lia­bil­i­ties of Ana­con­da Cop­per were inher­it­ed by the Atlantic Rich­field Com­pa­ny (ARCO), what lessons can be drawn for estab­lish­ing clear­er and more enforce­able legal frame­works that com­pel suc­ces­sor com­pa­nies to ful­fill their oblig­a­tions for post-min­ing envi­ron­men­tal and health­care responsibilities?

3. Giv­en the poten­tial vul­ner­a­bil­i­ty of the cleanup strat­e­gy to changes in pol­i­cy or fund­ing, what com­mu­ni­ty-led ini­tia­tives or part­ner­ships could be estab­lished to ensure the ongo­ing main­te­nance and mon­i­tor­ing of the Berke­ley Pit, inde­pen­dent­ly of fed­er­al man­dates or reg­u­la­to­ry shifts?

Pop­u­lar Media/News References:

SUPER­FUND-Under­stand­ing the Super­fund Process­Su­per­fund Terms & The Berke­ley Pit

Berke­ley Pit Landmark
https://www.visitmt.com/listings/general/landmark/berkeley-pit#:~:text=The%20Berkeley%20Pit%20is%207%2C000,which%20is%20filling%20with%20water.

EPA Announces Cleanup Deal For One Of The Biggest Super­fund Sites In The U.S.
https://www.npr.org/2020/02/16/806417345/epa-announces-cleanup-deal-for-one-of-the-biggest-superfund-sites-in-the-u‑s

Health Haz­ards from Min­ing in Butte, Montana
https://serc.carleton.edu/NAGTWorkshops/health/case_studies/butte_case_stud.html

In a tox­in-exposed Mon­tana min­ing town, the EPA favors polluters
https://crosscut.com/environment/2023/03/toxin-exposed-montana-mining-town-epa-favors-polluters

Envi­ron­men­tal Risks of Mining
https://web.mit.edu/12.000/www/m2016/finalwebsite/problems/mining.html

The Envi­ron­men­tal Dis­as­ter That is the Gold Industry
https://www.smithsonianmag.com/science-nature/environmental-disaster-gold-industry-180949762/#:~:text=Exposing%20the%20deep%20earth%20to,airborne%20elemental%20mercury%20every%20year.