Nevada Mercury Control Program (NMCP)
The Nevada Mercury Control Program (NMCP) is a State program that limits mercury emissions from thermal units at precious metal mines.
The NMCP reduces mercury emissions by requiring mines to install add on control technology. All facilities with SIC codes 1041 and 1044 are reviewed to determine if the NMCP applies. The rules focus on emissions from thermal processing units only.
The rules for the program are found in NAC 445B.3611 to 445B.3689.
- Visit NAC: CHAPTER 445B - AIR CONTROLS (external link)
Maximum Achievable Control Technology (NvMACT)
A key part of the program is NvMACT, the Maximum Achievable Control Technology chosen by NDEP under NAC 445B.3677.
Under NAC 445B.3625, any owner or operator who builds, changes, or runs a thermal unit that emits mercury must get a Mercury Operating Permit to Construct (Mercury OPTC). A facility must have this permit before it builds or modifies a thermal unit that emits mercury.
Federal permit requirements for gold mines
The U.S. EPA created 40 CFR Part 63 Subpart EEEEEEE, a federal air rule for gold ore processing. Under this rule, all affected facilities must have a Title V (Class I) permit, no matter how large or small they are.
- Visit eCFR :: 40 CFR Part 63 Subpart EEEEEEE -- National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area Source Category (external link)
Some gold facilities may need both a state NMCP permit and a federal permit under 40 CFR Part 63 Subpart EEEEEEE.
NMCP Annual Emissions Reporting
Facilities that use thermal units must report their yearly mercury emissions to the Nevada Division of Environmental Protection (NDEP). Reports are due every March.
NDEP reviews the information and publishes a summary report by July 1 each year.
To calculate emissions, facilities use the most recent NDEP approved Method 29 stack test and their actual production for the year. For full instructions, see:
- Download Annual Emissions Reporting Guide
- Download NMCP Method 29 Source Test Guidelines
- Visit Method 29 - Metals Emissions from Stationary Sources | US EPA (external link)
How NMCP reporting differs from TRI reporting
The Toxic Release Inventory (TRI) program requires facilities to report mercury or mercury compounds if they total 10 pounds or more in a year. TRI includes releases to air, water, land, and off site transfers.
The NMCP is different.
- NMCP reporting covers thermal units only (point sources).
- NMCP requires an approved Method 29 test from the same year as the report.
- A test must include an approved protocol, an NMCP witnessed test, and an approved final report.
A facility may use an NMCP approved test for TRI reporting. However, other TRI accepted data cannot be used for NMCP. Because the programs use different rules, their reported mercury values may not match.
Total reported mercury emissions by year
NMCP Documents
The NMCP is a detailed set of rules designed to reduce mercury emissions using NvMACT. Because the legal language can be difficult to read, NDEP created an overview and guidance document to explain the main concepts.
- Download NMCP Overview and Guidance
Program timelines
The NMCP includes specific timelines for applications, reviews, permit issuance, and installation of control technology. These programmatic events occur at the same time across the industry.
- Download NMCP Timeline
NMCP Wiki
The NMCP uses many mining and control technology terms. The NMCP Wiki explains these concepts in simple language.
- Download NMCP Wiki