Mine detail: Helen

Previously called 'AmericanDead Broke'

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Location

Lat / long:

38.74099, -122.70107

Resource(M)

Primary:	Mercury
Ore:	Cinnabar, Mercury, Metacinnabar
Gangue:	Opal, Pyrite
Orebody form:	IRREGULAR
Discovery year:	1871

Production

Operation type:	Unknown
Production size:	Small
Development status:	Past Producer
Production years:	1872, 1876, 1878 - 1881, 1902 - 1905, 1907 - 1924, 1926, 1928 - 1929, 1932 - 1940, 1942 - 1947

Geology

Host type:	Serpentinite,Basalt
Associated type:	Basalt
Structure:	Serpentine - Sandstone Contact
Alteration processes:	Silica Carbonate Alteration Of Serpentine, Kaolinization Of Basalt.

References

MRDS	M055681
DEP	10040806
Reference	{Deposit:: HOLMES, G. W., JR., 1965, MERCURY IN CALIFORNIA: IN USBM IC 8252}{Deposit:: BAILEY, E. H., USGS, PERSONAL FILES}{Deposit:: YATES, R. G. AND HILPERT, L. S., 1946, QUICKSILVER DEPOSITS OF THE EASTERN MAYACMAS DISTRICT, LAKE AND NAPA COUNTIES, CALIFORNIA: CALIF. JOUR. OF MINES AND GEOLOGY, V. 42, P. 231 - 286}{Deposit:: AVERILL, C.V., 1947, MINES AND MINERAL RESOURCES OF LAKE COUNTY, CALIF.: CJMG, V. 43, P. 15-38}{Deposit:: 5) BRADLEY, W.W., 1918, QUICKSILVER RESOURCES OF CALIFORNIA: CJMG BULL. 78, 389 P.}{Deposit:: 6) RANSOME, A.L. AND KELLOGG, J.L., 1939, QUICKSILVER RESOURCES OF CALIFORNIA: CJMG, V. 35, P. 353-558}{Deposit:: 1955 DIREXPL EATON AND SMITH CONTRACTOR}{Production:: USBM DATA}
Reporter	Peterson, Jocelyn A.