CEO Blog - May 13, 2011
Friday, May 13 2011 20:51
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Question: Comstock Mining has applied for a Mercury Permit. What is this and why is it required?

Answer: We expect our Mercury Permit from the State of Nevada Division of Environmental Protection (NDEP) very soon. This permit is regulated under the Nevada Mercury Control Program and is intended to ensure the safe and proper collection of mercury at a precious metal processing facility. Mercury is a naturally occurring metal found in very low concentrations in the indigenous ground of the Comstock Lode. When gold and silver ore is processed, a portion of the mercury that is also present is simultaneously extracted from the ore. The permit certifies that the proper equipment and procedures are in place to safely separate this mercury (through use of a Mercury Retort) and safely collect it for eventual shipment to an industry that uses mercury, such as the new low energy light bulb manufactures. The natural concentration of mercury is so low on the Comstock we estimate our processing could operate for a year and not even collect enough mercury to fill a 78 pound commercial flask. In other words, the amount of mercury commonly found in fluorescent light bulbs presents a much higher concentration. That said, we completely understand the need to operate safely and in complete compliance with all environmental concerns.

To be clear: Comstock Mining does not use mercury at any time in the processing of gold and silver. The equipment involved is routine and required for all Merrill-Crowe type processing facilities operating in Nevada. The retort equipment collects mercury vapor in a closed system, separates the metal, and then collects it. All the equipment is located in the processing facility at our American Flats location.

I think some confusion exists because the Comstock is an historic mining district. Prior to 1906, mercury was used in the amalgamating process to attach to and separate the gold and silver from the ore. To do this, mercury was utilized as a collection agent in the milling process as an amalgam and a significant portion of that mercury was unfortunately released into the environment. The miners at that time did not know the dangers of doing this. In 1906, the U.S. Bureau of Mines, in conjunction with the newly established MacKay School of Mines at University of Nevada, developed a cyanide vat leach process that effectively marked the end of mercury’s use in mining. Interestingly, the first mill to use this system in Nevada was the Donovan Mill located in Silver City, and the technology was almost immediately implemented on the Comstock because of its superior efficiencies.

The use of mercury on the historic Comstock is well documented from the original Carson River Superfund Site Investigation in the 1990s. Nevada’s Division of Environmental Protection (NDEP), supported by the U.S. EPA, continues monitoring these sites and is currently preparing an updated Archaeological Study to increase their understanding of the area. We do not see any conflict between NDEP’s efforts and our mining plans.  In fact, we are always ready, willing, and able to support NDEP’s efforts in these types of environmentally friendly endeavors.

Kindest regards,

Corrado De Gasperis
President and CEO