Mindat Logo

Grand National Mining Company Mine (Tangle Blue Mine), Tangle Blue Lake, Scott Mts, Klamath Mts, Trinity Co., California, USA

Latitude: 41°12'46"N
Longitude: 122°43'42"W
A former lode Au mine located in the SE¼NE¼ sec. 25, T39N, R8W, MDM, 1.5 km (5,000 feet) ENE of Tangle Blue Lake (coordinates of record), on the divide between Tangle Blue Creek and its tributary, Horse Creek, on Bureau of Land Management wilderness land (Trinity Alps Wilderness). Owned by Ezra E. Erich, French Gulch, California (1972). MRDS database stated accuracy for this location is 100 meters.

Mineralization is hosted in granodiorite, hornblendite and diorite. The ore body dips 90 (vertically), at a thickness of 1.22 meters. Ore controls included shearing planes in the host rock. Hanging wall in the drift to the N of the main adit, is a shear zone formed by hornblende diorite. Local rocks include Mesozoic granitic rocks, unit 5 (Klamath Mountains).

Workings include underground openings. The main adit was driven E for 700 feet on a 4 foot thick vein, then strikes the shear zone. A stope 100 foot long, 15 foot wide with a 60 foot face is situated above the adit level. Drifts on the main level, shear zone level, total 300 feet in length. A 100 foot crosscut was driven into the shear zone at 400 feet of depth. Also, a 50 foot deep winze was sunk below adit level on the shear zone. A short shoot of good ore was stoped from this to the main level.

Production data are found in: Averill (1937).

Production statistics: Year 1937 (period 1934 - 1937): 1,500 ounces Au, 2,200 ounces Ag and 1,900 pounds Cu. The shear zone was being mined for Au in 1937. No specific production record wasd found.

Analytical data results: Diorite in the shear zone assayed $3.50/ton in Au.

Mineral List

No entries listed.

The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Averill, Charles V. (1941), Mineral resources of Trinity County: California Journal of Mines and Geology, California Division Mines (Report 37): 37(1): 38.

McCulloch, W.C., Oesterling, W.A., Spurck, W.H., & Tischler, M.S. (1964), Minerals for Industry, Northern California, Southern Pacific Company: Vol. II: 135.

Hotz, Preston Enslow, Thurber, H.K., Marks, L.Y., and Evans, R.K. (1972), Mineral resources of the Salmon-Trinity Alps Primitive Area, California: U.S. Geological Survey Bulletin 1371-B, 267 pp.: 150.

USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10106546 & 10287772.

U.S. Bureau of Mines, Minerals Availability System (MAS) file ID #0061050185.

This page is currently not sponsored. To sponsor this page click here.

Mineral and/or Locality  
Search Google  
Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
Current server date and time: December 20, 2014 03:01:31 Page generated: July 17, 2012 16:41:57
Mineral and Locality Search
and/or Locality:
Fade toolbar when not in focusFix toolbar to bottom of page
Hide Social Media Links
Slideshow frame delay seconds