The US Bureau of Mines began the Minerals Availability System (MAS) n 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 Special Collections. The MAS files are arranged numerically by quadrangle number and indexed by quadrangle and property. The indexes, by quadrangle and property, are located next to the files. The quadrangle index is available at the ARLIS reference desk and in MAS Cases 1-4 in the Map Atrium, along with associated MAS maps and overlays.