Wharf Resources and DENR agree to settlement Officials from the South Dakota Department of Environment and Natural Resources (DENR) announced a settlement has been reached with Wharf Resources, a gold mining company near Lead. The settlement, which requires Wharf to come into full compliance and pay a $162,000 penalty, comes from a Notice of Violation DENR issued to Wharf Resources for violations of standards for two different nitrogen compounds in its various water sources.
The enforcement action addresses violations of Wharf's ground water discharge permit limits. After Wharf leaches gold from its crushed ore on the heap leach pads, it moves the spent ore off the pads to spent ore piles. The spent ore contains nitrogen in the chemical form of nitrate which is left over from explosives used to blast rock in the mine.
Precipitation has carried the nitrate into the localized ground water under the spent ore piles. Through time, nitrate in the localized ground water has built up to where it is greater than the 10 parts per million standard.
Wharf began pumping this localized ground water to a biological treatment system, but has had only partial success in reducing nitrate levels in the ground water. Therefore, the agreement requires Wharf to develop a plan, with biological specialists' consultation, to further reduce nitrate levels to meet the ground water standard.
Wharf has already tested and experienced initial success with a water treatment system using bacteria to consume nitrate in place in the localized ground water. The test results of this treatment program will be evaluated this summer, and an expanded treatment system may later be designed and implemented.
The other nitrogen compound Wharf has had problems with is ammonia. In 2002, Wharf added a process to its treatment system to remove selenium. When that modification occurred, Wharf's consultant recommended using a bacteria food source that contained ammonia. The ammonia from the food source passed through the treatment system and levels in the treated water were greater than ammonia limits established in Wharf's discharge permit.
Wharf corrected the problem with the biological treatment system and is back in compliance with the ammonia standard. However, the settlement requires Wharf to evaluate the treatment system's performance and add any other processes needed to meet standards. To meet that requirement, Wharf recently added a second biological treatment process to remove ammonia and a filter to remove suspended material from the treatment process.
"Making sure that companies follow the rules and protect our water resources is one of the most important things we do," said DENR Secretary Steve Pirner. "This action does that by requiring Wharf to take the necessary steps to ensure all of the water quality requirements that apply to its operation are met."
In additions to the $162,000 penalty, the settlement also includes automatic penalties if Wharf fails certain future ammonia or nitrate tests. Collections go to the state Regulated Substance Response Fund that is used for emergency cleanup actions.