With the cleanup of most of the hazardous chemicals completed at a closed gold and silver mill site about 10 miles west of Golden Valley off Highway 68, the Bureau of Land Management will conduct a study to determine the extent of contamination.
The BLM began the study in March to evaluate the extent of contamination discovered in 1999 at the 20-acre Tyro Mill site, according to a BLM press release.
The mill site is located at the remote site about five miles north of Highway 68 and roughly 10 miles east of Davis Dam and the Colorado River in the Black Mountains.
Despite the cleanup, some areas of toxic chemicals could still exist in the area.
The mill's milling equipment may also be contaminated.
Dead animals, reptiles and birds have reportedly been discovered in the area near the site.
The area is home to bighorn sheep, wild burros, large game and other desert animals and birds, the report stated.
A water quality impact study is also planned.
There is no evidence yet that the mill site has contaminated drinking water supplies, the report stated.
First identified in October 1999, the BLM began cleaning up and removing the most toxic materials in July 2000.
About 30 pounds of magnesium nitrate was found at the site.
Magnesium nitrate is highly flammable and explosive chemical, the report showed.
Soil contaminated with petroleum was also discovered.
Leakage and spillage from unauthorized use may have contaminated the soil with cyanide, arsenic and lead.
The extent of the contamination is still unknown.
Contaminated dust may still cause a hazard.
Contaminated tailings and mill waste also block two major dry washes.
Currently, the BLM has installed a security fence and warning signs around the mill site and along the primary access road blocking public access.
The mill's structures are also unstable and sinkholes are a threat to collapse.
The most serious materials found at the site during an inspection in May was highly concentrated cyanide used in the processing of gold and silver ore shipped to the site from local mines, the report stated.
Because of an interest to reopen the milling operation, an inspection took place in May 2000 leading to the discovery of the drums of corrosive chemicals and cyanide-laden sludge.
The site first opened in 1981 and closed down in 1984.
The mill is located near the Tyro mine first discovered in the 1860s and a major gold and silver producer.
At one time, it was the 10th largest gold producer in the state.
Cyanide is commonly used to separate the valuable minerals from the rock ore.
The highly toxic cyanide was found in a cement room at the site.
A cleanup crew had to used protective suits during the cleanup.
Enough cyanide coming in contact with human skin or by inhaling the fumes could cause death.
There are four levels of cleanup suits used with level A used for the most hazardous chemicals and level D as the lowest level.
The Tyro Mill cyanide cleanup required level B suits, consisting of full body coverage and air packs.
Water, with a high concentrate of bleach, was used to wash down the cyanide residue.
The rest of the less hazardous materials such as arsenic, lead and cadmium were scooped up and dumped in a five-acre pond near the mill site and finally removed.
The BLM is seeking public comment on the contamination cleanup evaluation.
Information can be obtained off BLM's website at http://azwww.az.blm.gov or by calling the BLM Kingman's office at 692-4408.