The Five Mines - Park Regent Mine
The Park Regent Mine is the northern most principle mine along the Amethyst Vein. In 1892 prospectors built a large surface plant to facilitate underground work and sank a large shaft into the vein. After the Silver Crash, a stamp mill was built by the property owners in an attempt to keep shipping costs low by concentrating ore. Intensive investigation below ground demanded more employees, and with them came more infrastructure. Residential buildings, large boilers, rail lines, and a mill were all part of the investment in the Park Regent Mine that failed to produce much ore. By 1912 the mine had yielded $25,000 worth of ore. Despite a brief resurgence in activity during World War I for economic ore, the mine has been silent since 1917.
The goal for remediation at the Park Regent Mine site was to reduce acid mine loading from the remnant waste rock piles. To accomplish this, 2,200 cubic yards of waste material was consolidated into approximately one acre area. The material was graded and capped with an impervious cement allowing water to shed off the pile without leaching metals. A diversion ditch around the pile was also constructed to discourage erosion, leaching and discharge from the road diversion ditch from flowing across the pile.
The area that formerly held the waste rock was covered with limestone to prohibit leaching of any remaining metals. Soil amendments and growth medium were then added to the site, followed by an appropriate seed mix to revegetate the landscape. To retain historic character the piles were not seeded for vegetation.
Reclamation at the Park Regent Mine will consist of consolidation of the mine waste, capping or liming of the surface, and diverting run-on water around the pile. Currently, acid-forming mine waste is spread over a large area. There is a vegetation kill zone covering in excess of ¼ acre below the waste pile. The Park Regent mine is a stop on the Bachelor Tour Route.
Approximately 1,000 cubic yards of waste is scattered on the east side of the main pile. This waste must be consolidated with the main pile in a triangular area on the east side. In addition, approximately 1,200 cubic yards of waste on the north end can be consolidated to reduce the footprint of the site. A small amount of the waste can be placed inside the capped, collapsed shaft. The entire consolidated waste pile must be graded to provide for positive drainage, but must be done in a manner that maintains the historic flavor of the site. The consolidated waste pile will cover approximately one acre.
Following consolidation of the waste rock, 13 tons of minus 40 mesh ground limestone must be uniformly applied to the removal area and the denuded area, then the area must be revegetated per:
Additionally, 40 tons of minus 40 mesh limestone must be applied to the consolidated waste rock. To maintain the historic flavor of this site, no revegetation will be done on the consolidated waste rock.
In order to reduce leaching and erosion from the pile, approximately 375 feet of diversion ditch must be constructed on the west side of the pile. The diversion ditch must be one foot in depth with 2h:1v side slopes. The excavated portion of the ditch must be placed on the downhill side of the ditch to form a berm with maximum slopes of 2h:1v.
The Park Regent Mine is a stop on the Bachelor Historic Tour. Therefore, the waste pile cannot be capped in-place or moved to a disposal area. In order to reduce the environmental degradation from the pile, the upper one foot of the consolidated waste pile will be cemented by the incorporation of a mixture of cement kiln dust (CKD) and cement.