Stillwater Mining Co. is proposing to drill at eight more sites along the Beartooth Face, east of its existing platinum and palladium mine, as geologists try to get a clearer picture of ore deposits in the mountainside.
“We actually proposed some different sites based on this year’s drilling,” said Randy Weimer, the mining company’s environmental manager in Columbus. “There are some gaps we need to fill. We’re proposing some additional sites to complete that picture.”
All of the drill sites are on the Custer National Forest in the general vicinity of the old Benbow chrome mine’s mill site near Dean. The Benbow Mill site is proposed as one of five staging areas to transport equipment by helicopter to the drill sites. Helicopters could be used as much as five times a day every day of the week to transport personnel and supplies.
The area along the Beartooth Face is popular with elk and deer hunters, provides access to the Absaroka-Beartooth Wilderness area for hikers and is also the site of a much-used ATV and jeep trail.
Stillwater Mining Co. operates the only platinum group metals mine in the United States. The mine features shafts on the west and east sides of the Stillwater River, as well as in the East Boulder River drainage farther northwest.
The proposed drilling will determine the potential for expanding the mine farther to the east. According to the company’s plan, “Depending upon the results of this exploratory drilling program, possible future development and implementation of the Blitz Mine Expansion has the potential to add an additional 25 years or more of mine life to Stillwater Mining Company’s operation.”
Drilling was delayed earlier this summer by wet weather and continued into December, according to Bob Cronholm, of the Montana Department of Environmental Quality, which permits the project for the state. Ruen Drilling, of Clark Fork, Idaho, is drilling the bore holes. Work in 2014 is planned to run from May to October.
Cronholm said the core samples — which are about 2 inches in diameter and can measure 1,000 to 6,000 feet long — require an assay to determine the amount of precious metals.
“It’s not like it would stick out,” he said of the platinum and palladium. “Their sulfides are pretty minor.”
Platinum-group elements are contained in magmatic sulfide deposits.
The hole drilled for the alignment of the mine portal was the deepest drilled – about 6,000 feet deep, Cronholm said. The geology in that area, which features rock stacked at opposing angles, prompted the mining company to reassess its original portal plan, he added.
“They don’t call it the Stillwater simple; it’s complex,” he said of the Stillwater igneous complex, the name given to the large, layered intrusion. An intrusion is liquid rock that forms under the earth’s surface.
Because of the high mountain location of some of the drill sites – 7,200 to 8,800 feet – some whitebark pine trees may be removed. Stillwater Mining said a Forest Service representative would review the drill sites prior to “site preparation to pre-approve removal of all large trees and all live whitebark pine trees. Whenever possible, felling of healthy cone-bearing whitebark pine trees will be avoided.”
Whitebark pine is considered warranted for listing as an endangered species because of shrinking populations, but has not been protected because of other federal priorities. The trees produce nuts that are an important food for several species, including grizzly bears.
The Beartooth Ranger District, which oversees the permitting of the project, is seeking public comments on Stillwater Mining’s proposal. Work would be concentrated in the Nye Creek drainage, where six of the drill sites would be located.
Drills would be operated 24 hours, seven days a week. Up to 12 people would be at the drill locations, punching as many as 15 holes. Disturbance on the ground would be limited to about 40 feet square.
“They keep their disturbances pretty minimal,” Cronholm said.
No mining, milling or permanent facilities are planned. All disturbed areas at the drill sites are required to be reclaimed.
Helicopters would fly drilling equipment into the sites, meaning no new roadways would be built. Water for drilling would be hauled in or tapped from nearby streams. The drills may require up to 25 gallons a minute of water to cool the diamond-tipped bits and flush the cuttings. Drill cuttings and fluids are collected in a sump. When done, the drill holes are backfilled with bentonite to within 6 to 10 feet of the surface and then capped with cement.
Stillwater Mining Co. has posted a $250,000 reclamation bond and agreed to monitor the drill sites for weed infestations for three years.
Cronholm said Stillwater Mining Co. is “always a pleasure to work with. They go above and beyond.”
For further information on the proposal, to obtain a copy of the plan of operations, to provide public comment, or to be added to the mailing list, contact Dan Seifert at the Beartooth Ranger District at 446-2103; or by email at: firstname.lastname@example.org.
Public comments will be used to determine the level of analysis and identify any issues relating to Stillwater Mining’s proposal.
Comments or input addressing the plan of operation should be submitted by Jan. 27 to Beartooth R.D. (6811 US Highway 212 South, Red Lodge, MT 59068).
Written comments from the public to the Forest Service from the previous drilling project included concern by some residents about what the mine’s expansion might mean to the area, requests for further regulation and a complete halt to the drilling. A few people spoke in favor of the jobs the operation might create and the Stillwater County commissioners endorsed the project.