Mexico’s Supreme Court recently published the public version of the judicial Amparo proceedings filed by residents of a community against the authorization to construct and operate a mine tailings dam in the northern state of Sonora. The case came to court from a petition filed at a District Court alleging that the Ministry of the Environment and Natural Resources (SEMARNAT) had not consulted with the communities’ residents before issuing the permits, even though there is no current legal need to do so and even though the community is located several kilometers away from the project site. The decision is part of a series of decisions gradually cementing the state’s duty to hold public consultations with local communities before issuing environmental permits.

Case Summary

Residents of Bacánuchi, a small community located about 80 km south of the project site, challenged the permit on the basis that authorities had failed to hold a public consultation with the community. In its decision, the Court recalled that Bacánuchi was one of seven communities affected by 2014s spillage of 40 thousand cubic meters of copper sulfate which reached the Bacánuchi River, causing health and environmental damages. In light of the potential damages, the Court ruled that issuing the permit to construct a mine tailings dam without consulting the residents of the neighboring community violated Mexico’s Constitution and International Human Rights Law.

Legal Framework

Like most countries, Mexican law requires permits for activities that may pose a risk for the environment, including —among others— the construction and operation of mine tailings dams. The law has two procedures for filing permits: a) filing an environmental impact statement (EIS) or b) filing a preventive impact assessment (PIA). Generally, all projects require an EIS, which implies filing an assortment of technical studies. The law allows filers to substitute the EIS with a PIA —a less rigorous procedure— when projects meet certain legal conditions. One of these conditions is that the project or the activities are regulated by Official Mexican Standards (NOMs). Since official standards are mandatory and establish the requirements that products or services must meet to protect people and the environment, the underlying premise is that the standards offer sufficient safeguards to allow the filer to forego the additional requirements of the EIS. This is the case of mine tailing dams, which are regulated by NOM-141-SEMARNAT-2003.

Among the differences between an EIS and a PIA, is that the law includes public consultations as part of the authorization process for the EIA. The goal of public consultations is to give residents an opportunity to manifest their concerns and suggest preventive measures. The public consultation is not mandatory, though, and must be requested by the community’s residents. With this decision, the Court essentially eliminates this distinction and makes public consultations a prerequisite for PIAs as well.

In its decision, the Court ordered authorities to hold a public meeting that explains the technical environmental aspects taken into account for the site’s construction, the possible impacts of its operation, and the preventive measures considered. The ruling requires that residents be given the opportunity to express their concerns and suggestions. It is unclear how this mandate will affect permits, since public consultations are not binding, yet the Court calls on authorities to use all available means to avoid any significant damages to the environment once the consultation has taken place.

What you need to know

  • The court’s ruling sets a standard establishing the need to consult every community that could be affected by projects that may have adverse environmental effects.
  • The ruling even applies to cases where the activity is regulated by NOMS or official standards and regulations, even though current law does not require public consultations to be held in these cases.
  • The Court’s ruling does not set rules or guidelines for the public consultation and instead relies on the current guidelines.
  • The results of public consultations are not binding on the government’s decision to approve projects, yet the Court goes beyond current law and states that authorities must use all available means to avoid significant damages to the environment;
  • Congress recently published its’ legislative agenda for the year. In it, Congress recognized the need for a public consultations law. Even though a public consultation law was enacted in 2014, it mostly applies to cases of national interest and does not apply to environmental cases.
  • If a public consultation law is not enacted, it is likely that the Court will continue to define the right to public consultations on a case by case basis which would ultimately subject permits to judicial proceedings and delay projects for years.


The Supreme Court is gradually cementing the duty for government agencies to hold public consultations before issuing environmental permits. This includes cases where the law currently does not require public consultations. Even though the decision is not considered legal precedent, it sets the direction the court will take on following cases. Furthermore, it opens the door for more claims, with the potential of delaying environmental permits with lengthy judicial proceedings.