Robertson - Triplet Project

Producer in Lander county in Nevada, United States with commodity Gold

Geologic information

Identification information

Deposit ID 10310462
MRDS ID W700593
Record type Site
Current site name Robertson - Triplet Project
Alternate or previous names Robertson South Joint Venture, Tenabo Mine, Robertson Mine, Triplet Gulch project (Lode), 39A Zone, Altenburg Hill, Gold Pan Zone, Porphyry Zone, Widow's Mine Zone
Related records 10106938

Comments on the site identification

  • This record combines all information from the earlier MRDS records W700593, M242954, M242953 for individual portions of this project.

Geographic coordinates

Geographic coordinates: -116.69482, 40.31185 (WGS84)
Relative position The project area is located on te west edge of Crescent Valley about 80 km southwest of Elko.
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Geographic areas

Country State County
United States Nevada Lander

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 028N 047E 08 09 16 17 Nevada

Comments on the location information

  • The mine area is located near the mouth of Triplet Gulch and Mill Gulch just south of the historic site of Tenabo.


Commodity Importance
Gold Primary

Comments on the commodity information

  • Ore Materials: free gold

Materials information

Materials Type of material
Gold Ore

Mineral occurrence model information

Model code 75
USGS model code 19c
BC deposit profile E03
Deposit model name Distal disseminated Ag-Au
Mark3 model number 18
Model code 173
USGS model code 26a.1
Deposit model name Sediment-hosted Au
Mark3 model number 17

Host and associated rocks

  • Host or associated Host
    Rock unit name Valmy Formation
    Stratigraphic age (youngest) Ordovician

Nearby scientific data

(1) -116.69482, 40.31185

Economic information

Economic information about the deposit and operations

Operation type Surface-Underground
Development status Producer
Commodity type Metallic
Significant Yes
Year of first production 1989
Year of last production 1989
Production years 1989

Mining district

District name Bullion District

Land status

Ownership category Private
Ownership category BLM Administrative Area
Area name Battle Mountain BLM-administrative district

Ownership information

  • Type Owner-Operator
    Owner Coral Gold Resources Ltd.
    Year 2004

Comments on the workings information

  • There are numerous old surface and underground workings in the area with more recent open pit development. Some of the early development work was on the placer deposit in Triplet Gulch, but the more recent development is on the lode deposits.

Comments on other economic factors

  • Reserves for the Robertson deposit in 1988 were reported as 11 million tons of ore grading 0.04 ounces of gold per ton. In 1993 a geologic resource of 20 million tons grading 0.036 ounces of gold per ton and in 1996 a geologic resource of a million ounces of gold was reported for Robertson. Reserves for the Triplet deposit in 1988 were reported as a million tons of ore. In 2000, a drill indicated resource of 4.7 million tons of ore grading 0.077 ounces of gold per ton was reported for the 39A deposit. In 2000, a drill indicated resource of 2.1 million tons of ore grading 0.019 ounces of gold per ton was reported for the Altenburg deposit, and in 1999, 21,300 measured ounces of gold was reported. In 2000, a drill indicated resource of 6.1 million tons of ore grading 0.28 ounces of gold per ton was reported for the Gold Pan deposit, and in 1999, 91,400 measured ounces of gold was reported. In 2000, a drill indicated resource of 20 million tons of ore grading 0.02 ounces of gold per ton was reported for the Porphyry deposit, and in 1999, 254,678 proven and probable reserve ounces of gold were reported. In 2000, a drill indicated resource of 2.9 million tons of ore grading 0.016 ounces of gold per ton was reported for the Widow's Mine deposit, and in 1999, an inferred 37,300 ounces of gold were reported. The only reported lode production for Robertson was 3,700 ounces of gold in 1989.

Comments on development

  • The deposit was discovered in the mid-1980s, and ore production capacity was expected to be between 300,000 and 500,000 tonnes/year. Further drilling was anticipated in 1988 to further delineate the northern extent of the orebody. Mining was to begin in fall of 1988 and to last about 3 years, but production was only reported for 1989 before operations ceased. Explration resumed in the early 2000s and in 2002, Coral Gold Corp. began a 9,000-foot drill program on their Robertson South joint venture property. The drilling was focused in two areas where previous drilling encountered anomalous gold mineralization. In 2004, Coral Gold Resources Ltd. announced that it had received approval from the Bureau of Land Management to conduct additional exploratory drilling at its 100% owned Robertson Property. Drilling was to commence in November 2004 and was expected to take less than one month to complete. The new program will consist of drilling 10 reverse circulation holes totaling about 7,000 ft. The purpose of the drilling is to expand the current indicated mineral resources in the 39A and Porphyry Zones. These resources are currently estimated to contain 2.8 million tons of mineralized material at a grade of 0.101 oz Au/t and 3.95 million tons of mineralized material at a grade of 0.040 oz Au/t, respectively. The drilling will be targeted specifically at expanding high-grade portions of the two resources. The best results from the April 2004 drilling program in the 39A Zone were returned in hole CR04-8, which intersected 135 ft that averaged 0.074 oz Au/t, from 600 ft, using a 0.02 oz Au/t cutoff grade. Included within this intercept is a 30 ft interval that averaged 0.229 oz Au/t, starting at 675 ft.

Reference information

Bibliographic references

  • Deposit

    Mining Magazine, January 1989, p. 44.

  • Deposit

    Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States; Part A, Database description and analysis; part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.

  • Deposit

    Coral Resources, Inc., 1988, Plan of operations for the proposed Triplet Gulch Project, Lander Co., Nevada: on file at NBMG.

  • Deposit

    Bonham, H.F., 1988, in NBMG MI-1987.

  • Deposit

    Press clippings, NBMG Mining District File 151.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-DEC-2004 LaPointe, D. D. Nevada Bureau of Mines and Geology
Editor 01-SEP-2007 Schruben, Paul G. U.S. Geological Survey Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.