Progress in Modern Tailings Dam Safety and Regulation in the United States

Over the past several years, significant events in the world of mine tailings dams included fatal incidents and environmental impacts. Compelled to find a better way, the mining industry, concerned citizens, and state and federal regulators began intense reviews of mining practices and the respective statutes and regulations. Montana, British Columbia (B.C.) and Alberta led the way with legislative updates to the body of law governing mining in those jurisdictions. Technical organizations published updated guidance manuals, and academics, consultants, and dam owners held conferences and committee meetings around the world. New committees were formed in Canada and the United States, including the Dam Integrity Advisory Committee of the Alberta Chamber of Resources and the Tailings Dam Regulatory Committee of the Association of State Dam Safety Officials (ASDSO). Mining companies and trade associations advocated member policies and recommendations on modern mine waste management and engineering. In Montana, the State Legislature adopted Senate Bill 409, amending the Montana Annotated Code to address a detailed standard of care for mine reclamation, including the design, construction, operation, and closure of tailings storage facilities. Alaska published draft guidance on the applicability of existing dam safety statutes and regulations to dams at mines and mine tailings dams. Most significantly, and largely unrelated to recent mine tailings dam failures, the U.S. Environmental Protection Agency (EPA) proposed draft rules for financial responsibility demonstrations for certain contingencies at operating mines nationwide. After considering public comments and other information, the EPA made a final decision not to adopt those rules. In summary, the EPA determined that “modern mining practices and modern environmental regulations” effectively mitigated the risks for which the proposed rules were intended to address. The EPA appeared to overlook the reduction in risk provided by state dam safety programs but did acknowledge they provide “further safeguards” (USEPA, 2018). In fact, dam safety concepts are fundamental to mitigating risks at tailings storage facilities. The following presents a review of the advent of modern tailings dam safety practice and the role of risk reduction provided by dam safety, mine regulation, and other programs.