Prior to closing a mine the following must be determined with the help of the State Land Department:
- Is the mine on State Land? If not, it is referred to the proper federal agency if it is on federally managed lands or, if on private land, the owner is ascertained through federal and county records.
- If the mine is on State Land, does it have an active lease or claim? If it does not, the closure may proceed. If it does, the lessor must be required to fence the mine and post warning signs.
- What is the history of the mine? The Department of Mines and Mineral Resources (ADMMR) must be contacted for a copy of the mine's history. The State Land Department arranges for the State Historical Preservation Office to assess the mine site. This agency also has their archeologists conduct a study of the site, and determine the impact of the closure on the cultural resources of the mine.
- Are there any endangered species living in or around the mine that would be impacted by a closure? The Arizona Fish and Game Department must be contacted to assess the mine openings for bats and other endangered species. Endangered and threatened plants must also be assessed for possible impact by mine closure.
- Is there any potential for future renewed mining of the site? ADMMR's history files and a site investigation by a geologist or mine engineer is the best way to determine future potential.
- Given the above considerations, what is the best type of closure for the mine? A mine with sensitive species or potential future use should be closed using a bat gate or other semi-permanent closure. Mines without these can be filled or capped to fully protect the public.