Latitude: 57°54'34"N
Longitude: 134°59'24"W
The deposit is on 6 patented claims that were acquired by Kaiser Gypsum Company in the late 1950's.
Location: The Kaiser Gypsum Mine is at an elevation of about 80 feet on an unnamed north tributary of Gypsum Creek. The mine is in the SE1/4 sec. 2, T. 46 S., R. 64 E. It is location P-21 of Bittenbender and others (1999), MAS no. 0021140041 (U.S. Bureau of Land Management, 2002). The location is accurate.
Geology: The rocks in the vicinity of the Kaiser Gypsum Mine are part of the Mississippian, Iyoukeen Formation (Lathram and others, 1965). The upper half of the formation is fossiliferous cherty limestone; the lower half is fossiliferous shale with minor limestone. A Cretaceous hornblende-biotite quartz monzonite stock is about 1.5 miles north of the mine. The deposit was discovered in 1902 and was soon acquired by Pacific Coast Gypsum who developed it with two shafts, a raise, and 3,500 feet of drifts to a depth of 300 feet (Wright and Wright, 1907; Burchard, 1920; Steward, 1932; Flint and Cobb, 1953; Bittenbender and others, 1999). They operated the property from 1906 to 1923 and produced about 500,000 tons of gypsum. In 1923, the mine flooded and closed. It is unclear, however, whether it closed because it had exhausted the deposit and the company decided to stop pumping a wet mine or the flooding made the deposit uneconomic. Roppell (1973) has a particularly informative history of the discovery of the deposit, the personalities and companies involved, and the history of mining to the end of production. The deposit is on 6 patented claims that were acquired by Kaiser Gypsum Company in the late 1950's. The deposit was drilled by the U.S. Bureau of Mines in the 1960's. Unpublished data from industry in the office of the U.S. Bureau of Land Management in Juneau, Alaska, indicate that a reserve of 4.5 million tons of gypsum may remain (Bittenbender and others, 1999). The origin of the deposit is unclear and most people who have described it are uncertain whether it is a bedded syngenetic deposit or an epigenetic deposit related to a nearby quartz monzonite intrusion (Wright and Wright, 1907; Burchard, 1920; Steward, 1932; Flint and Cobb, 1953; Bittenbender and others, 1999). At least locally, the deposit is underlain by limestone breccia and overlain by conglomerate. Solution cavities filled with gravel are common. The structure of the deposit is complex with much folding and faulting, and the gypsum is deformed. The deposit is cut by thin basaltic dikes. At the 300 level of the mine, the workings covered an area about 600 by 800 feet and at the 160-foot level, the workings were about 500 by 1000 feet. An anhydrite vein 6 inches to more than 10 feet thick was found on the 160-foot level.
Workings: The deposit was discovered in 1902 and was soon acquired by Pacific Coast Gypsum who developed it with two shafts, a raise, and 3,500 feet of drifts to a depth of 300 feet (Wright and Wright, 1907; Burchard, 1920; Steward, 1932; Flint and Cobb, 1953; Bittenbender and others, 1999). In 1923, the mine flooded and closed. It is unclear however, whether it closed because it had exhausted the deposit and the company decided to stop pumping a wet mine or the flooding made the deposit uneconomic. The deposit was drilled by the U.S. Bureau of Mines in the 1960's.
Age: If sedimentary, the gypsum is Mississippian, the age of the formation that hosts it. If epigenetic, the gypsum may be related to nearby Cretaceous quartz monzonite.
Production: Pacific Coast Gypsum operated the mine from 1906 to 1923 and produced about 500,000 tons of gypsum. Roppell (1973) has a particularly informative history of the discovery of the deposit, the personalities and companies involved, and the history of mining to the end of production.
Reserves: Unpublished data from industry in the files of the U.S. Bureau of Land Management in Juneau, Alaska, indicate that a reserve of 4.5 million tons of gypsum may remain (Bittenbender and others, 1999).
Commodities (Major) - Gypsum
Development Status: Yes; medium
Deposit Model: Gypsum of debatable origin.
References
Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p. Brooks, A.H., 1913, Mineral resources of Alaska, report on progress of investigations in 1912: U.S. Geological Survey Bulletin 542, 308 p. Brooks, A.H., 1915, Mineral resources of Alaska; report on progress of investigations in 1914: U.S. Geological Survey Bulletin 622, 380 p. Brooks, A.H., 1918, Mineral resources of Alaska, 1916: U.S. Geological Survey Bulletin 662, 469 p. Brooks, A.H., 1919, Alaska's mineral supplies: U.S. Geological Survey Bulletin 666-P, p 89-102. Brooks, A.H., 1921, The future of Alaska mining, in Martin, G.C., and others, Mineral resources of Alaska, 1917: U.S. Geological Survey Bulletin 714-A, p. 5-57. Brooks, A.H., 1922, The Alaska mining industry in 1920: U.S. Geological Survey Bulletin 722-A, p. 1-74. Brooks, A.H., 1923, The Alaska mining industry in 1921: U.S. Geological Survey Bulletin 739-A, p. 1-50. Brooks, A.H., 1925, Alaska's mineral resources and production, 1923: U.S. Geological Survey Bulletin 773-A, p. 3-52. Brooks, A.H., and Capps, S.R., 1924, The Alaska mining industry in 1922: U.S. Geological Survey Bulletin 755-A, p. 1-56. Buddington, A.F., and Chapin, Theodore, 1929, Geology and mineral deposits of southeastern Alaska: U.S. Geological Survey Bulletin 800, 398 p. Burchard, E.F., 1920, Alaska, in Stone, R.W., and others, Gypsum deposits of the United States: U.S. Geological Survey Bulletin 697, p. 47-48. Chapin, Theodore, 1916, Mining developments in southeastern Alaska: U.S. Geological Survey Bulletin 642-B, p. 73-104. Cobb, E.H., 1972, Metallic mineral resources map of the Sitka quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-467, scale 1:250,000. Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Sitka quadrangle: U.S. Geological Survey Open-File Report 78-450, 124 p. Flint. Jr., G.M., and Cobb, E.H., 1953, Gypsum deposits near Iyoukeen Cove, Chichagof Island, southeastern Alaska: U.S. Geological Survey Bulletin 989-B, p. 27-37. Gnagy, W L., 1962, Some notes on, and a tentative summary of, the genesis of the gypsum deposits at the Pacific Coast Mine, Gypsum Creek and Gypsum Camel, Iyoukeen Cove, Chichagof Island, southeast Alaska: Unpublished petrographic report, No. 2-43, U. S. Bureau of Mines, 5 p. (Report held by the Mineral Information Center, Bureau of Land Management, Juneau, Alaska.) Gustafson, F.D., 1946, Preliminary report on the geology of Camel Gypsum, Alaska: Alaska Territorial Dept. of Mines Miscellaneous Report 114-6, 5 p. Herreid, G., 1962, Camel Gypsum property and Pacific Gypsum property, Sitka quadrangle: Alaska Division of Mines and Minerals Property Examination 114-14, 5 p., 1 map. Jermain, G.D., and Rutledge, F.A., 1952, Diamond drilling the Gypsum-Camel prospect, Iyoukeen Cove, Chichagof Island, southeastern Alaska: U. S. Bureau of Mines Report of Investigations 4852, 6 p. Knopf, Adolph, 1912, The Sitka mining district, Alaska: U.S. Geological Survey Bulletin 504, 32 p. Lathram, E.H., Pomeroy, J.S., Berg, H.C., and Loney, R.A., 1965, Reconnaissance geology of Admiralty Island, Alaska: U.S. Geological Survey Bulletin 1181-R, p. R1-R48. Loney, R.A., Berg, H.C., Pomeroy, J.S., and Brew, D.A., 1963, Reconnaissance geologic map of Chichagof Island and northwestern Baranof Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-388, 1 sheet, scale 1:250,000. Loney, R.A., Brew, D.A., Muffler, L.J.P., and Pomeroy, J.S., 1975, Reconnaissance geology of Chichagof, Baranof, and Kruzof Islands, southeastern Alaska: U.S. Geological Survey Professional Paper 792, 105 p. Martin, G.C., 1920, The Alaska mining industry in 1918: U.S. Geological Survey Bulletin 712-A, p. 1-52. Moffit, F.H., 1927, Mineral industry in Alaska in 1925: U.S. Geological Survey Bulletin 792-A, p. 1-39. Redman, Earl, 1989, Mining gypsum at Iyoukeen Cove: Unpublished report, 5 p. (Report held by the Mineral Information Center, Bureau of Land Management, Juneau, Alaska.) Roppel, Patricia, 1973, Gypsum: Alaska Journal, V. 3, no. 3, p. 149-152. Smith, P.S., 1926, Mineral industry of Alaska in 1924: U.S. Geological Survey Bulletin 783-A, p. 1-30. Smith, P.S., 1930, Mineral industry of Alaska in 1928: U.S. Geological Survey Bulletin 813-A, p. 1-72. Smith, S.S., 1917, The mining industry in the Territory of Alaska during the calendar year 1915: U.S. Bureau of Mines Bulletin 142, 65 p. Smith, S.S., 1917, The mining industry in the Territory of Alaska during the calendar year 1916: U.S. Bureau of Mines Bulletin 153, 89 p. Stewart, B.D., 1932, The occurrence of gypsum at Iyoukeen Cove, Chichagof Island: U.S. Geological Survey Bulletin 824-F, p. 173-177. Twenhofel, W.S., Reed, J. C., and Gates, G.O., 1949, Some mineral investigations in southeastern Alaska: U.S. Geological Survey Bulletin 963-A, p. 1-45. U.S. Bureau of Land Management, 2002, Alaska mineral locations database report (Sitka quadrangle), July 2, 2002, 205 p. [
http://imcg.wr.usgs.gov/dem.html [Link dead. Jul 2011]] Wright, C.W., 1907, Lode mining in southeastern Alaska: U.S. Geological Survey Bulletin 314, p. 47-72. Wright, C.W., 1908, Lode mining in southeastern Alaska, 1907: U.S. Geological Survey Bulletin 345-B, p. 78-97. Wright, C.W., 1909, Mining in southeastern Alaska: U.S. Geological Survey Bulletin 379-B, p. 67-86. Wright, F.E., and Wright, C.W., 1905, Economic developments in southeastern Alaska: U.S. Geological Survey Bulletin 259, p. 47-68.
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