New regulation requires mining to manage its waste with management plans

The Ministry of Environment and Natural Resources (SEMARNAT) published this Wednesday, September 9, 2026, in the Official Gazette of the Federation, the Official Mexican Standard NOM-157-SEMARNAT-2026, which establishes the elements and procedures for implementing mining waste management plans. The standard, which is mandatory for those who generate and possess mining waste, replaces NOM-157-SEMARNAT-2009 and will enter into force 180 calendar days after its publication.

The instrument was issued by SEMARNAT and signed by Ileana Augusta Villalobos Estrada, Undersecretary of Environmental Regulation and president of the National Consultative Committee for Environmental and Natural Resources Standardization, following its approval as definitive during the Second Extraordinary Session of the committee, held on July 28, 2026.

A stricter framework for the mining industry

The new standard updates the list of mining waste and reinforces the responsibility of operators. According to articles 17 and 42 of the General Law for the Prevention and Integral Management of Waste, waste generated by the exploration, exploitation, processing, or utilization of a mining concession is the permanent and non-transferable responsibility of the concession holder, even if its management is carried out through a third party, who will share said responsibility jointly and severally.

Among the changes compared to the 2009 version, the following stand out:

• Waste not exclusive to mining processes, such as filter cloths, spent catalysts, and activated carbon, are excluded from the list and must be reclassified as hazardous or special management waste.
• Waste inherent to the activity is incorporated, such as material from the disintegration, crushing, and classification of minerals, simple or complex sulfates, calcium or magnesium carbonates, and clays.
• The category “spent mineral from the bioleaching process” is added.
• The exclusion of waste from metallurgical processes is removed; these must now be characterized by the presence of toxic elements such as arsenic, cadmium, antimony, and selenium.

Content and evaluation of management plans

The management plan must include objectives, the waste subject to the plan, a generation baseline, the address of the facilities, a description of the management procedure, a program of activities, the estimated generation period, and evaluation and improvement mechanisms. The standard provides the alternative of a comprehensive characterization study to forecast potential environmental damage and defines maximum permissible limits for toxic constituents such as arsenic, cadmium, mercury, lead, and selenium.

Verification and surveillance are the responsibility of SEMARNAT through the Federal Attorney for Environmental Protection (PROFEPA), which may perform the conformity assessment when no accredited private infrastructure exists. Previously authorized management plans will remain in effect, although the holder may request their update in accordance with the new provisions.

Impact on the sector

The standard affects the entire mining industry in the country, which in open-pit mining operations can generate up to 90% of waste per unit of mineral, according to SEMARNAT itself. By prioritizing reduction at the source, recovery, and treatment over final disposal, the new framework seeks to minimize waste generation and prevent risks to health and ecosystems, in line with the UN Sustainable Development Goals.

Source: Official Gazette of the Federation, no. 245/2026, September 9, 2026, First Section, pp. 60-78 (official reference: NOM-157-SEMARNAT-2026).