A faulty test cylinder containing 150 pounds of chlorine sprang a leak at a Clarkdale mineral extraction operation, releasing a small amount of chlorine gas, but injuring no one, Clarkdale Minerals Development Manager Tom Piccioli said.
The test cylinder is one of three chlorine storage units located at the plant subject to regular inspections by the U.S. Mine Safety and Health Administration and the Arizona Department of Environmental Quality. Two different cylinders containing potentially deadly chlorine currently operate the plant, said James Murray, Clarkdale Minerals project manager.
The leak was caused Aug. 24 by a valve that was not properly attached to the test cylinder due to defective threads, Piccioli said.
“At no time was anyone in any danger whatsoever,” he said.
The leak was discovered shortly after 7:30 a.m. when a strong odor of chlorine was detected in the experimental area. According to standard procedures in such situations, all employees were evacuated to a central area away from the laboratory, Murray said.
Employees wearing protective gear entered the laboratory with chlorine sensors to verify the leak and then called Clarkdale Fire District to the scene.
“The leak was minor but rendered the building unsafe to occupy,” according to Clarkdale Fire Chief Joe Moore.
The Clarkdale Fire District secured the scene and called in the Camp Verde Fire District hazardous materials team.
Using a special tool for such situations, the CVFD team capped the cylinder within 12 minutes of entering the laboratory. A short time later, the company that originally delivered the cylinder removed it from the scene, Murray said.
Because the leak was so small, Moore decided there was time to call in other agencies to take part in an impromptu training exercise, Murray said.
Verde Valley Ambulance Co. provided medical and rehabilitation services as needed, Cottonwood Fire Department conducted decontamination operations and Jerome Fire Department watched out for the crews on scene.
“In my opinion, they did an excellent job,” Piccioli said.
The primary chlorine cylinders used to operate the plant are located in a separate building. The cylinder that leaked was located in a lab where technicians are investigating new processes to increase the yield of metals from slag, Murray said.
“The two primary cylinders that operate the plant are in full compliance with all state and federal laws,” Murray said. “We have triple redundant alarms that will shut down systems. The building is monitored 24 hours a day. We have not had any incidents” since the company began using chlorine in February.
Located at 500 Luke Lane, Clarkdale Minerals uses chlorine to extract gold, silver and other minerals from the pile, which contains about 20 million tons of material. The pile contains about 0.5 ounces of gold per ton, along with silver, copper, zinc and a ferro silicate byproduct, according to the company’s parent, Searchlight Minerals.