Montana Resources officials on Friday estimated the tally of snow geese who may die in the contaminated Berkeley Pit water could reach into the hundreds.
An estimated 10,000 migrating snow geese found respite in the pit lake during a snow storm Monday night. MR employees shining a spotlight on the water reported seeing the lake “white with birds,” said Mark Thompson, MR’s manager of environmental affairs.
Thompson estimates 90 percent of the birds have taken flight since then. But a few hundred float in a group east of the pit's center. They appeared unwilling to leave as of Friday afternoon. A handful of lone stragglers dot the water’s surface.
Company officials say the situation doesn’t look good for the remaining birds. Employees intensified hazing efforts Friday morning by adding sonic-like blasts from the side of the pit. Since Monday night, MR employees have been shooting high-powered rifles and have used various other automated sounds to encourage the birds to take flight.
The automated sounds are part of MR’s bird hazing program. Designed by federal and state agencies, that program has kept flocks of birds off the water for more than two decades, company officials said.
Thompson said after this week’s situation, MR intends to investigate adding speakers to a drone to haze birds.
It has been 21 years – almost to the day – since 342 snow geese landed on the Berkeley Pit as the result of a winter storm. The storm likely held those geese captive on the water. A few days later, the Bureau of Mines stumbled on the dead birds during a routine visit, according to previous stories.
That incident attracted national media attention.
Sensitive to the legacy of the 1995 die-off, MR officials have been consumed since Monday night with trying to get the birds to leave.
“We’re fighting like hell to get them out of the pit,” said Thompson.
State and federal agencies paid visits to assess the situation Tuesday and Wednesday. MR is working with U.S. Fish and Wildlife Service to identify and recover birds, an agency official said Thursday.
The recovery may take time, however. Due to ongoing concerns of pit wall sloughing, MR officials cannot get on the water.
The pit’s lake is around 700 acres, or a little more than a square mile, in size. In 1982, Atlantic Richfield Company turned off the pumps that had prevented groundwater from entering into the open-pit copper mine. Since then, the Berkeley Pit has been slowly filling with water laden with heavy metals and high in sulfuric acid. Previous reports hold that the acid is what killed the 1995 snow geese.
According to a 1995 study conducted by the state, recovered dead snow geese suffered burned throats. There were also signs of kidney damage, likely due to an excess of heavy metals ingested.
The 1995 report also notes that two of the dead birds studied came from a ranch about 40 miles away in Beaverhead County.