Minerals & Metals

Terms & Definitions

Alloy
A mixture of metals.

Baghouse
A facility at a smelter used to capture dust from a variety of sources, including storage areas, lead smelting and refining operations. The dust is captured and recycled.

Behavior Based Safety (BBS)
A system used internationally, often by manufacturing industries, which uses demonstration, one-on-one observation, and job feedback to recognize safe behaviors and explore behavioral reasons for unsafe acts.

Chat
A gravel-like waste product from the milling/mining process used before froth flotation was developed in the 1920s. Chat contains minor amounts of lead, zinc and other metals.

Electrowinning
In a specialized tank, a current is passed from inert carbon-based anodes through a liquid leaching solution, which contains dissolved metal. The electrical current causes the metal to be deposited onto cathodes where it is later harvested.

Emissions
The gases and particles put into the air or emitted by various sources.

Environmental Protect Agency (EPA)
The national federal agency whose mission is to protect human health and safeguard the natural environment.

Finished-grade Lead
Material that has been smelted and refined for delivery to customers. Doe Run’s lead is 99.99 percent pure.

Galena
Lead sulfide, the most common type of lead ore.

Leaching
A low-temperature, wet-chemical process carried out in a series of tanks that is used to dissolve metal contained in feed material into the solution.

Lead
A soft, malleable and dense metallic element that is extracted chiefly from galena. It also is found in ore with zinc, silver and copper.

Lead Concentrate
A term used to describe the lead product created after raw ore is milled, then physically separated from waste rock (tailings).

Lead Smelting
The process of reducing lead-bearing material into metallic lead in a furnace. The result is refined lead.

Milling
The process that extracts most, but not all, of the desirable mineral from the lead ore through screening, crushing and grinding.

Mine Safety and Health Administration (MSHA)
The federal enforcement agency responsible for the health and safety of miners.

Missouri Department of Natural Resources (MDNR)
The Missouri governing body that provides assistance, education and guidance in the use and protection of Missouri’s natural resources.

National Ambient Air Quality Standards (NAAQS)
Air quality standards set by the EPA for pollutants considered harmful to public health. In October 2008, the EPA adopted a revised NAAQS for lead: 0.15 micrograms of lead per cubic meter of air (µg3) measured in a rolling three-month average. The results are often called air-lead levels.

Occupational Safety and Health Administration (OSHA)
The federal agency charged with enforcing safety and health legislation, specifically for the workplace.

Ore
A naturally occurring mineral containing a valuable constituent (as metal) for which it is mined and worked.

Primary Lead Smelting
Lead metal produced from extracted lead-bearing ore. Primary lead is sometimes called virgin lead.

Polymetallic Ore
Ore that contains lead, zinc, copper, silver and other metals.

Processed Lead
Finished-grade lead.

Remediation or Reclamation
Activities conducted to restore sites impacted by mining and mineral processing, by removing the materials and stabilizing the surface, or by encapsulation.

Secondary Lead
Lead produced from recycling lead-bearing material.

Sinter
The two- to four-inch chunks of solid material that result from roasting sulfur away from lead concentrate. This material becomes feed for the blast furnace.

Slag
A byproduct of lead smelting. Slag is a glassy, sand-like material containing small amounts of lead, zinc, copper and other materials.

State Implementation Plan (SIP)
A U.S. state plan for complying with the federal Clean Air Act. It is administered by the EPA and consists of rules, agreements and technical documentation that an individual state will use to clean up polluted areas. SIPs are prepared by state government, approved by the EPA and monitored by state environmental agencies. In Missouri, that monitoring agency is the MDNR.

Sulfuric Acid Plant
Doe Run’s acid plant, located inside its primary lead smelting operation, collects the sulfur dioxide from the sinter plant and converts it into sulfuric acid, which is sold to fertilizer manufacturers.

Tailings
Ground-up rock that is the byproduct of milling and mining; often called the “tail end” of the mining process.

Toxic Release Inventory (TRI)
A list of materials maintained and updated annually by manufacturers and filed with the EPA as required under Title III of the Superfund Amendments and Reauthorization Act (SARA) of 1986.