TY  - RPRT
TI  - A simplified economic filter for open-pit gold-silver mining in the United States
AU  - Donald A. Singer
AU  - W. David Menzie
AU  - Keith R. Long
PY  - 1998
DO  - 10.3133/ofr98207
UR  - https://pubs.usgs.gov/publication/ofr98207
ID  - ofr98207
ER  -