MAS Files (also called Mineral Assessment Studies or Mineral Availability System;  later known as AMIS, Alaska Minerals Information System) 

The Minerals Availability System (MAS) was a US Bureau of Mines program begun in the early 1960’s to measure and classify identified mineral resources according to their extraction technologies, economics and commercial availability.  The files contain information on occurrences, deposits, mines and processing facilities. 

When the US Bureau of Mines was closed in 1996, the US Bureau of Land Management (BLM) was given responsibility for the Alaska MAS files located in Juneau and Anchorage.  Those files in BLM are known as AMIS, Alaska Minerals Information System.  The paper version of the Alaska MAS files was housed at the John Rishel Mineral Information Center in Juneau until July 2008 when the Center closed and the files were transferred to ARLIS.  

Most of the information in the MAS files from Juneau is now available online at the links below. The paper files from Juneau and from Anchorage are available for use at ARLIS. Both the digital files and the paper files are arranged by quadrangle or mining district.

• Mineral Availability System reports, by quadrangle number/place/ mining district

• Locating a Paper MAS file