Berkeley Pit
E790403
Berkeley Pit is a former open-pit copper mine in Butte, Montana, now a highly acidic, contaminated lake and a notable environmental Superfund site.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Berkeley Pit canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T9305831 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Berkeley Pit Context triple: [Butte, Montana, hasLandmark, Berkeley Pit]
-
A.
Bear Lake
Bear Lake is a scenic alpine lake in Colorado’s Rocky Mountain National Park, popular for its easy-access hiking trails and striking mountain views.
-
B.
Bear Lake
Bear Lake is an inland lake in Muskegon County, Michigan, known for recreational activities such as boating and fishing and its connection to the larger Muskegon Lake.
-
C.
Jezioro Gardno
Jezioro Gardno is a coastal lake in northern Poland, located near the Baltic Sea within the Słowiński National Park.
-
D.
Soda Lake
Soda Lake is a dry alkali lakebed in the Mojave Desert of California, known for its white mineral crusts and stark desert landscape.
-
E.
Pickle Lake
Pickle Lake is a remote northern community in Ontario, Canada, known as one of the province’s most northerly road-accessible towns and a service hub for nearby First Nations and mining activities.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Berkeley Pit Target entity description: Berkeley Pit is a former open-pit copper mine in Butte, Montana, now a highly acidic, contaminated lake and a notable environmental Superfund site.
-
A.
Bear Lake
Bear Lake is a scenic alpine lake in Colorado’s Rocky Mountain National Park, popular for its easy-access hiking trails and striking mountain views.
-
B.
Bear Lake
Bear Lake is an inland lake in Muskegon County, Michigan, known for recreational activities such as boating and fishing and its connection to the larger Muskegon Lake.
-
C.
Jezioro Gardno
Jezioro Gardno is a coastal lake in northern Poland, located near the Baltic Sea within the Słowiński National Park.
-
D.
Soda Lake
Soda Lake is a dry alkali lakebed in the Mojave Desert of California, known for its white mineral crusts and stark desert landscape.
-
E.
Pickle Lake
Pickle Lake is a remote northern community in Ontario, Canada, known as one of the province’s most northerly road-accessible towns and a service hub for nearby First Nations and mining activities.
- F. None of above. chosen
Statements (51)
| Predicate | Object |
|---|---|
| instanceOf |
Superfund site
ⓘ
open-pit copper mine ⓘ toxic lake ⓘ |
| closureReason |
declining copper prices
ⓘ
high operating costs ⓘ |
| contaminant |
arsenic
ⓘ
cadmium ⓘ copper ⓘ heavy metals ⓘ sulfuric acid ⓘ zinc ⓘ |
| country |
United States of America
ⓘ
surface form:
United States
|
| county | Silver Bow County, Montana NERFINISHED ⓘ |
| createdBy | expansion of underground mining operations to open-pit mining ⓘ |
| designatedAsSuperfund | 1983 ⓘ |
| economicRole | major copper producer during mid-20th century ⓘ |
| endDate | 1982 ⓘ |
| environmentalImpact |
long-term water contamination
ⓘ
wildlife mortality ⓘ |
| environmentalStatus | U.S. EPA Superfund site ⓘ |
| floodingBegan | 1982 ⓘ |
| hasFeature | viewing platform for tourists ⓘ |
| location | Butte, Montana NERFINISHED ⓘ |
| managedBy |
Montana Department of Environmental Quality
NERFINISHED
ⓘ
U.S. Environmental Protection Agency NERFINISHED ⓘ |
| mineralExtracted |
copper
ⓘ
gold ⓘ molybdenum ⓘ silver ⓘ |
| miningMethod | open-pit mining ⓘ |
| near | downtown Butte, Montana ⓘ |
| notableEvent |
mass death of snow geese in 1995
ⓘ
recurring bird mortality incidents ⓘ |
| operatedBy |
Anaconda Copper Mining Company
NERFINISHED
ⓘ
Atlantic Richfield Company NERFINISHED ⓘ |
| ownedBy | Atlantic Richfield Company NERFINISHED ⓘ |
| partOf |
Butte mining district
NERFINISHED
ⓘ
Silver Bow Creek/Butte Area Superfund site NERFINISHED ⓘ |
| remediationPlan | Berkeley Pit water treatment system NERFINISHED ⓘ |
| replaced | part of the historic Butte Hill neighborhood ⓘ |
| risk |
potential contamination of regional groundwater
ⓘ
potential overflow into surrounding waterways ⓘ |
| startDate | 1955 ⓘ |
| state | Montana NERFINISHED ⓘ |
| threatens |
Clark Fork River
NERFINISHED
ⓘ
Silver Bow Creek NERFINISHED ⓘ |
| touristAttraction | yes ⓘ |
| waterColor | reddish-brown ⓘ |
| waterLevel | monitored and controlled ⓘ |
| waterpH | highly acidic ⓘ |
| waterType | acid mine drainage ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Berkeley Pit Description of subject: Berkeley Pit is a former open-pit copper mine in Butte, Montana, now a highly acidic, contaminated lake and a notable environmental Superfund site.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.