The MPCA reissued the general permit for construction sand and gravel, aggregate and hot mx asphalt facilities. Because of changes to the latest version, the permit will retain the same permit number (MNG490000) but titled "Nonmetallic Mining and Associated Activities."
This webpage is intended to help you determine what type(s) of water quality permit is required at facilities that mine construction sand and gravel; industrial sand; quarry limestone, granite or dimension stone; operate hot mix asphalt production areas; produce concrete block, brick and other products; and/or produce ready-mix concrete. In addition, this Web page provides basic information about the general permit.
Applicability: do you need a permit?
Any facility that is engaged in an activity described below is required to obtain stormwater permit coverage. This can be accomplished through several permitting options. The chart below should help you determine which type of permit is most appropriate for your facility and activities. Contact the MPCA staff person listed at the bottom of this page if you have questions about the chart.
- Construction sand and gravel mining (Standard Industrial Classification [SIC] Code 1442)
- Industrial sand mining (SIC Code 1446)
- Dimension stone (SIC Code 1411)
- Crushed and broken limestone mining/quarry area (SIC Code 1422)
- Crushed and broken granite mining/quarry area (SIC Code 1423)
- Crushed and broken stone mining/quarry area (not elsewhere classified, SIC Code 1429)
- Hot mix asphalt production areas (also known as asphalt paving mixtures and blocks (SIC Code 2951). This includes portable hot mix asphalt plants.
- Concrete block and brick (SIC Code 3271)
- Concrete products other than block and brick (SIC Code 3272)
- Ready-mix concrete (SIC Code 3273). This includes portable concrete plants.
The General Permit for Nonmetallic Mining and Associated Activities (MNG490000) is a specific type of permit covering both stormwater and wastewater. It is also a multi-site permit, meaning all qualifying sites can be covered with a single permit application. This permit authorizes wastewater discharges to surface waters of the state from:
- Dewatering from mine and quarry areas at construction sand and gravel and industrial sand mining – Subsector J1 facilities
- Dewatering from mine and quarry areas at dimension stone, crushed and broken limestone, crushed and broken granite, and other crushed and broken stone facilities – Subsector J2 facilities.
This permit authorizes wastewater discharges from the following activities that do not discharge to surface waters of the state. If there is a surface water discharge, an individual permit is required.
- Wash water from Subsector J1 and J2 facilities.
- Dredging operations from Subsector J1 and J2 facilities.
- Installation, construction, and operation of wet scrubbers at hot mix asphalt production areas, including portable hot-mix asphalt plants (Subsector D1).
- Washing trucks, mixers, transport buckets, forms and/or other equipment at concrete block and brick, concrete products other than block and brick, and ready-mix concrete facilities (Subsector E2).
- Uncontaminated scale deck wash water that does not use detergents, solvents, or degreasers.
- Stormwater and deck wash water collected in holding tanks under scales.
- Wash water associated with cleaning of mobile equipment that does not use detergents, solvents, or degreasers.
- Waters used for dust control on crushers, conveyors, associated equipment, and site roadways.
This permit authorizes non-stormwater discharges to surface waters of the state. These discharges are the same as those covered under the Industrial Stormwater General Permit (MNR050000).
- Emergency fire-fighting activities.
- Fire hydrant and fire suppression system flushing.
- Potable water line flushing.
- Uncontaminated condensate from air conditioners, coolers, and other compressors and from the outside storage of refrigerated gases or liquids.
- Landscape watering provided all pesticides; herbicides and fertilizers have been applied in accordance with manufacturer’s instructions.
- Pavement wash waters where no detergents are used and no spills or leaks of potential pollutants such as fertilizers, salts, or toxic and hazardous materials have occurred unless all spilled material has been removed.
- Routine external building wash down that does not use detergents, solvents, or degreasers.
- Uncontaminated groundwater or spring water.
- Foundation or footing drains where flows are not contaminated.
- Incident windblown mist from cooling towers that collects on rooftops or adjacent portions of the facility, but not intentional discharges from the cooling tower (e.g., “piped” cooling tower blowdown or drains).
This permit also includes materials approved in Minn. R. 7035.2860 (Beneficial Use of Solid Waste) at sites engaged in activities associated with all SIC Codes listed above. Any recycling and storage of these materials must meet the requirements of Minn. R. 7035.2855 (Solid Waste Storage Standards). It also includes associated activities, such as maintenance activities, unless otherwise specified as NOT being covered in the permit (see next section).
Stormwater discharges associated with construction activities from the above sites are also covered under this permit. Therefore, additional coverage under the Construction Stormwater General Permit (MNR100001) is not required.
This permit includes active sites, temporarily inactive sites and inactive sites. Temporarily inactive sites are sites that are not currently undergoing mining or associated activities, but permit coverage is being maintained for the possibility of mining in the foreseeable future. The Permittee must ensure Best Management Practices are in place at temporarily inactive sites. Inactive sites are sites where mining has ceased. Permit coverage can be terminated once the Permittee achieves final stabilization of the inactive site (see Section 2.6.29 of the permit).
What does this permit NOT cover?
- Dewatering of mine or quarry areas other than those under Subsector J1 and J2.
- Surface water discharges of scrubber or other air emissions control wastewater, cooling or boiler wastewater, floor drains from process areas, equipment/vehicle washing, cleaning and maintenance wastewaters, and sewage.
- Contaminated ground water discharges.
- Petroleum refineries.
- Facilities that manufacture asphalt or asphalt emulsions.
- Industrial sand mines (SIC 1446) that utilize HF flotation.
- Dredging or filling of wetlands or other surface waters of the state.
- Discharges of hazardous substances, lubricants, fuel leaks, or fuel spills.
- Sites for which Environmental Assessment Worksheets or Environmental Impact Statements are required by Minn. R. ch. 116D and/or 42 U.S.C. Sec 4321 - 4370f, until that environmental review is completed.
- Existing discharges or new and expanded discharges that will cause or contribute to a violation of water quality standard unless it meets the requirements of 40 CFR 122.44 and 122.4(i), respectively.
- Discharges that adversely impact or contribute to the impact on a listed endangered or threatened species
- Discharges that adversely affect properties listed or eligible for listing in the National Register of Historic Places or known/discovered archeological sites.
- Discharges to calcareous fens listed in Minn. R. 7050.0335, subp. 1.E.
- Mine site dewatering discharges from Subsector J1 and J2 facilities to the following receiving waters:
- Outstanding Resource Value Waters (ORVW)
- Department of Natural Resources (DNR)-designated trout waters.
- DNR-posted fish-spawning areas.
If you perform any of these activities above, an Individual NPDES/SDS Permit may be required for discharges to waters of the state. Please contact the MPCA with questions.
Adding and removing sites from the Nonmetallic Mining and Associated Activities Permit
To add or remove sites from permit coverage, submit the site inventory report form:
Apply for coverage: Permit information and forms
Apply for permit coverage for all qualifying sites using the following forms:
Fill out the Permit Change Request form below for name changes, transferring ownership or if all pits have closed and ceased operations.
Comply with the general permit requirements
The principal requirements of the general permit (MNG490000) are summarized below. Refer to the permit linked a the top of the page for exact permit language, terms and conditions.
- The permittee must meet the water-quality based effluent limits and technology-based effluent limits in the permit. These include specific control measures for both stormwater and wastewater. Control measures, or best management practices (BMPs) can be structural or non-structural. Structural BMPs include physical structures like stabilization ponds, sedimentation basins, vegetative swales, or infiltration devices. Non-structural BMPs include activities, like good housekeeping to control sediment from vehicle tracking.
- A pollution prevention plan (P2 plan) must be prepared and implemented for each site before the site is covered under the permit. This plan includes both stormwater and wastewater management. Specific standards for P2 plans are specified in the general permit.
- A discharge monitoring report (DMR) form is required for each stormwater discharge at a site covered under the general permit. Stormwater must be sampled twice per year and reported on the MPCA's DMR form by January 21 of each calendar year (see sections 2.6.141 - 2.6.154 of the general permit).
- If dewatering occurs, monitoring is required quarterly and a DMR must be submitted by 21 days after the end of each calendar quarter following permit issuance (see section 2.6.155 to 2.6.161 of the general permit).
- A monthly inspection by facility-designated personnel at each site is required to ensure that the plan is being followed, with at least one inspection being conducted during a runoff event. Inspections must be documented.
- Inlet/outlet flow protection is required at dewatering sites.
- Flow related limits and monitoring information for pit dewatering is required.
- Design and construction standards for wet scrubber impoundments, if present at hot-mix asphalt facilities, are specified in the general permit.
Assistance. See the small business environmental assistance pages for helpful compliance calendars that reference the MNG49 water permit and air permits.
Submit required reports
The annual reports required by the previous permit have been replaced by facility-specific DMR forms. The DMR is required for each stormwater discharge at a site covered under this permit. Submit DMRs electronically using MPCA's online e-Service. Learn more on the wastewater reporting page.
Stormwater must be sampled twice per year and submitted by January 21 for results from the preceding calendar year. If dewatering occurs at Subsector J1 or J2 facilities, monitoring is required quarterly and a DMR must be submitted by quarterly (by Jan. 21, April 21, July 21 and Oct. 21) for results from the preceding calendar quarter. See Section 8 of the general permit linked above for specifics on monitoring. See the industrial stormwater sampling pages for useful information on when and how to take samples:
NEW: If your site contains a 10 year, 24-hour storm event control basin, you may be eligible for a monitoring waiver. To request a waiver in monitoring, you must have a professional engineer construct (for new facilities) or verify (for existing facilities) that the stormwater control device and/or the dewatering control device can contain the volume from a 10 year, 24-hour storm event. Limits must be met, but no monitoring is required.
Comply with other (MPCA and non-MPCA) requirements
In addition to the water quality concerns at these types of facilities, other environmental considerations may require additional permitting or oversight by various governmental entities.
- Water withdrawals — A water appropriation permit from the Department of Natural Resources may be required if more than 10,000 gallons of water per day or 1 million gallons per year is being withdrawn from a state water (including ground water, as in pit/quarry dewatering).
- See the DNR website for details.
- Conditional Use Permit — A conditional use permit for mining activities may be required by the county.
- See the Minnesota Law Library, which lists ordinances for many cities and counties.
- U.S. Army Corps of Engineers — Activities that involve the discharge of dredged or fill material or excavation within waters and wetlands may require approval of the Corps of Engineers. Such activities could include the construction of access roads or the creation of storage areas and building sites. Also, activities related to the construction of pit dewatering outfall structures and the excavation of water detention/retention ponds within waters and wetlands may require Corps approval. For more information, visit the U.S. Army Corps of Engineers.
- Environmental review — If a new pit or quarry is started, or an existing one is expanded by 40 acres or more, and the pit will have a mean depth of at least 10 feet during its existence, the project needs to have an environmental assessment worksheet prepared. If the new pit or expansion will cover at least 160 acres, mined to a mean depth of 10 feet or more, an environmental impact statement is needed. Learn more:
- Fuel and hazardous materials management — When equipment is refueled, maintained or repaired outside the shops, special care must be taken to prevent spills, and to quickly contain and collect accidental spills. Used oil, lubricants, antifreeze, paint, solvents, vehicle cleaning wastes, recovered freon, asbestos, PCBs and shop wastes should be properly contained stored, and recycled or disposed of in compliance with MPCA requirements. Learn more: Hazardous waste
- Tanks — Liquid (including fuel) storage tanks, whether aboveground or underground, need to have effective containment and may need to be approved by the MPCA. Learn more: Storage tanks
- Air quality management — All facilities must meet minimum standards for dust and noise control. Facilities with crushing operations may have to meet additional federal standards for emissions of particulates from processing equipment. It is important to control dust throughout the facility, including at crushers, screens, conveyors and hoppers. The use of fuels, other volatile chemicals, and/or generators may also dictate additional air quality requirements. Depending on production capacity and processing equipment, an Air Emission Permit may be required. Learn more: Air permits
- Solid waste management — Some aggregate operations store used asphalt and/or concrete, captured particulate emissions, or other demolition debris. The MPCA encourages recycling of these materials, and of scrap and trash materials, when possible. If this is not practical, used pavement must be disposed of in an approved sanitary or demolition debris landfill. Learn more: Waste and recycling permits and regulations