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Overview of nonferrous metallic mining

Nonferrous metallic mining has occurred in Wisconsin since the time of the Copper Culture about 2,000-5,000 years ago. Mining for metals such as copper, lead and zinc shaped the history of several regions of Wisconsin and played a major role in the development of Wisconsin as a state.

The DNR is the state agency with primary responsibility for regulating environmental aspects of metallic mineral exploration and mining activities. Within DNR, the Environmental Analysis and Sustainability Program has the lead role in reviewing applications for mining permits and coordinating the required environmental impact analysis of a proposed mining project, including the preparation of an environmental impact statement. In addition to a mining permit, most mining operations would also require a number of other permits and approvals issued by the DNR, such as those related to discharge of wastewater, stormwater management, construction and operation of a solid waste facility, construction in or near navigable waterways, withdrawal of groundwater and protection of wetlands and air quality. Specialists from a number of other programs, for example, Fisheries, Wildlife and Forestry, would also be involved in the review of any major mining project.

The state nonferrous mining law was most recently updated in 2018, with the promulgation of 2017 Wisconsin Act 134, followed by administrative rule updates in 2020 to ensure consistency with the statutory changes. A summary of these changes is listed on page 4 of the "Summary of DNR Regulation of Nonferrous Metallic Mining in Wisconsin" document below.


Exploration drilling is the primary method used to define and characterize a potential mineral deposit and ultimately determine if the deposit is a potentially economically viable orebody. In Wisconsin, exploration refers to the on-site geologic examination from the surface of an area by core, rotary, percussion or other drilling method, where the diameter of the hole cannot exceed 18 inches. Exploration drilling is conducted for the purpose of searching for nonferrous metallic minerals or establishing the nature of a known nonferrous metallic mineral deposit and includes associated activities, such as clearing and preparing drilling sites and constructing access roads.

Prior to conducting exploration, an explorer must first obtain an exploration license from the DNR. The application for an exploration license must be accompanied by the appropriate fee and a surety bond. The amount of the surety bond will vary but must be in an amount adequate to cover the costs of properly restoring all exploration drilling sites constructed by the explorer. This statewide license is valid for one year and must be renewed each year as long as the explorer retains bonding liability for any exploration drilling sites.

Once an explorer has identified a potential mineral occurrence and wishes to conduct an exploration drilling program, they must submit a detailed exploration proposal, or notice of intent, to the DNR for review. This proposal delineates the project timeline, means and methods of exploration, site access and preparation, water and drilling fluid management, potential impacts on water resources, best management practices, endangered resource review, drill hole abandonment procedures and reclamation plans. If a notice of intent meets the requirements specified in the state laws and rules, approval or conditional approval is granted to the explorer. Any updates or changes to the notice of intent may affect the DNR's decision and must be approved by the DNR prior to implementation. The explorer must also acquire all other DNR, local or federal permits and approvals before exploration work can commence.

Following the completion of drilling, each exploration site must be properly reclaimed, and each drill hole must be permanently abandoned by filling the drill hole from the bottom to the top with cement grout or other approved material. DNR staff will conduct inspections prior to initiation of any disturbance, during site preparation, during drilling, at the time of permanent abandonment of drill holes and following reclamation of the drilling site.

The explorer will be responsible for the reclamation procedures defined in the notice of intent. A surety bond must be posted by the explorer in an estimated amount sufficient for the DNR to complete reclamation if the explorer abandons the project. Once the DNR determines the site is fully reclaimed in accordance with the notice of intent and state standards, a certificate of completion will be issued. The bond will be held for one additional year to ensure site success.


Bulk sampling is the process of extracting a representative portion of a mineral deposit or orebody for evaluation and analysis. An excavation of up to 10,000 tons of metallic mineral deposit material can be allowed and typically includes overburden. The purpose is to obtain site-specific data to assess the quality and quantity of the deposit and analyze the excavated materials in order to prepare the application for a mining permit. Manual removal of rock samples from the ground surface, outcrops or nonferrous mineral exploration are not considered bulk sampling.

The first step in the bulk sampling process is acquiring a bulk sampling license through the DNR. This application requires the development of a bulk sampling plan, including a detailed description and timeline for all proposed activities, best management practices for stabilization and revegetation and a cost estimate for reclamation. A bond in the amount estimated to cover the full costs of reclaiming the area disturbed by bulk sampling activities must be in place prior to onsite work. As with exploration drilling, all necessary permits and approvals from the DNR, local and federal entities must be acquired before the commencement of operations.


For mining proposals, the permitting process can take several years. Before a mining permit may be issued, an applicant must provide the DNR with considerable information about the proposed project. Metallic mining project construction and development may proceed only if the DNR grants a mining permit with its approval of the environmental monitoring, mining, and reclamation plans, along with all other permits and approvals required by the DNR. The applicant may also need to apply for permits from other regulatory agencies, such as the Wisconsin Public Service Commission or the U.S. Army Corps of Engineers and must also obtain all necessary approvals from local jurisdictions.

Under the mining law, if the DNR determines the proposed mining project will comply with all applicable environmental protection laws and rules and receives local zoning approval, the DNR must issue a mining permit. If a DNR review concludes that requirements of any applicable state laws and rules could not be met by a proposed mining project, the DNR cannot issue a mining permit.

During the mining permit review process, the DNR works with many parties, including residents, tribal governments, other state and federal agencies, local officials and mining company representatives. Agency staff often work closely with mining company officials and consultants to familiarize them with state mining regulations, standards and environmental and public review steps. By working closely with interested parties, the DNR can better understand all aspects of the proposed project and its potential effects.

Because the DNR regulates mining in Wisconsin, it has no position for or against mining. The DNR is responsible for conducting a thorough review of any proposed project to determine compliance with all applicable laws, codes and environmental protection standards and that all conditions in any mining permit will be monitored and enforced.

Get more details on the mine permitting process.