1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Domingo District

Producer in Gunnison county in Colorado, United States with commodities Gold, Silver, Sulfur, Copper, Tellurium, Lead, Zinc, Selenium, Bismuth, Thorium, Vanadium
Map
XML
JSON
KML
B

Geologic information

Identification information

Deposit ID 10014386
MRDS ID D011132
Record type District
Current site name Domingo District
Alternate or previous names Vulcan District, Patented Claims: Vulcan, MS 10909, War Eagle, MS 10910, Humming Bird, MS 10910, Rose Bud, MS 10910, Iron Clad, MS 10910, Della S., MS 11243, Morning Star, MS 11243, St.Patrick, MS 12175, Mammoth Chimney, MS 12454, Good Hope, MS 12456, Lincoln, MS 13156, Golden Slipper, MS 13179, Humboldt, MS 16392, Branch, MS 17215, Eclipse, MS 17390, Yellow Rose, MS 17390, Laura Belle, MS 19038, Mill Site Lode, MS 19920

Geographic coordinates

Geographic coordinates: -107.00173, 38.34528 (WGS84)
Elevation 2719
Relative position 14.3 MILES S 15 TO 20 W FROM GUNNISON
(click for info)

Geographic areas

Country State County
United States Colorado Gunnison
United States Colorado Saguache

Public Land Survey System information

Meridian Township Range Section Fraction State
New Mexico 047N 001W 07,08 Colorado

Comments on the location information

  • DISTRICT OCCUPIES LESS THAN TWO SQ MI OF AREA IMMEDIATELY AROUND OLD SITE OF VULCAN. MOST PROPERTIES LIE ADJACENT TO CAMP CREEK AND BETWEEN CAMP CREEK AND LITTLE CAMP CREEK. DISTRICT EXTENDS EASTWARD ONTO SPRING HILL CREEK (1962) QUAD AND IS ACCESSIBLE VIA ROAD UP CAMP CREEK VIA WILLOW CREEK SOUTH FROM U.S. 50 AND BLUE MESA RESERVOIR; VIA ROAD EAST FROM WILLOW CREEK, MIDWAY, AND COLORADO RTE 149; VIA ROAD WEST ACROSS CORRAL AND WRIGHT CREEKS FROM SUGAR FROM SUGAR CREEK. ELEV AND LAT-LONG GIVEN ARE FOR OLD TOWN SITE OF VULCAN ON CAMP CREEK IN SW SE NE SEC. 07, T47N, R1W. ; INFO FROM LAND.ST :1976

Commodities

Commodity Importance
Gold Primary
Silver Primary
Sulfur Secondary
Copper Secondary
Tellurium Tertiary
Lead Tertiary
Zinc Tertiary
Selenium Tertiary
Bismuth Tertiary
Thorium Tertiary
Vanadium Tertiary

Comments on the commodity information

  • TETRADYMITE (BI2TE2S) WAS NOT DEFINITELY RECOGNIZED BUT INFERRED ON BASIS OF ANALYSES OF NATIVE TE, RICKARDITE, AND ARSENOPYRITE. VULCAN AND MAMMOTH-GOOD HOPE MINES ARE TYPE OF LOCALITIES FOR RICKARDITE (CU3TE2) AND WEISSITE (CU5TE3). AURIFEROUS PYRITE AND PETZITE ARE PRINCIPAL AU-BEARING MINERALS. THE NEW TELLURIDE, VULCANITE (CUTE OR CU7TE5), WAS IDENTIFIED ABOUT 1960. GOOD HOPE MINE IS ONLY COLORADO OCCURRENCE OF BERTHIERITE (FESB2S4); SINGLE SPECIMEN NOTED BY RICKARD (1903). ROSCOELITE NOT DEFINITELY IDENTIFIED BUT INFERRED BY RICKARD (1903) ON BASIS OF ASSOCIATION WITH RICKARDITE, WEISSITE, AND NATIVE TE.

Materials information

Materials Type of material
Chalcopyrite Ore
Copper Ore
Galena Ore
Gold Ore
Petzite Ore
Rickardite Ore
Sphalerite Ore
Sulfur Ore
Sylvanite Ore
Thorite Ore
Chlorite Gangue
Coloradoite Gangue
Jasper Gangue
Limonite Gangue
Magnetite Gangue
Pyrrhotite Gangue
Quartz Gangue
Sericite Gangue
Tetradymite Gangue

Alteration

  • (Local) Oxidation Of Pyrite To Fe Oxides And Native S; Sericitization And Chloritization Of Schist Near Mineralized Zone; Supergene Alteration Of Cu Sulfide To Covellite; Supergene Alteration Of Tellurides To Native Te And Cu Tellurides (Rickardite, Weissite, Vulcanite)

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Carbonatite, Intrusive
    Stratigraphic age (youngest) Late Cambrian
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Trachyte
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
    Rock unit name Granite Of Tolvar Jpeak;Trachyte And Trachyte Porphyry Dikes;Carbonatite;Quartz Vein
    Rock description Granite Of Tolvar Jpeak;Trachyte And Trachyte Porphyry Dikes;Carbonatite;Quartz Vein
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Trachyte
    Rock unit name Dubois Greenstone--Felsite And Felsite Porphyry;Dubois Greenstone--Quartzite
    Rock description Dubois Greenstone--Felsite And Felsite Porphyry;Dubois Greenstone--Quartzite
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granite

Nearby scientific data

(1) -107.00173, 38.34528
ListMap

Geologic structures

Type Description Terms
Regional Gunnison Uplift, San Juan Volcanic Field
Local Gunnison Gold Belt, Iron Hill Alkalic Complex, Tolvar Peak Stock

Controls for ore emplacement

  • Massive Sulfide Deposition Controlled By Original Depositional Environment In Submarine Volcanic Sequence. Precious Metals And Tellurides Localized In Silica Vein System Near Hanging Wall Of Lens (Stratigraphic/Structural Discontinuity). Native S/Se Localized In Oxidized Portion Of Sulfide Lens Above Present Water Table. Th Occurrence Apparently Controlled By Mineralogy In Discordant Trachyte Dikes.

Economic information

Economic information about the deposit and operations

Development status Producer
Commodity type Both metallic and non-metallic
Deposit size Small
Significant No
Discovery year 1894
Discovery method Ore-Mineral In Place
Year of first production 1898
Year of last production 1983

Mining district

District name Domingo (Vulcan) District

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Webbco, Cleveland, Tx. (Vulcan Resources, Inc., El Paso, Tx) (Mammoth-Good Hope Mine)
    First year 1983
  • Type Owner
    Owner Herron Mining Co. (Mammoth-Good Hope Mine)
    First year 1983

Comments on the workings information

  • DUE TO FLATTER TERRAIN, MOST MINES AND CLAIMS WERE DEVELOPED BY SHAFTS AND OPEN CUTS, LESS SO BY UILLSIDE ADITS. MAMMOTH-GOOD HOPE AND VULCAN WORKINGS (PRINCIPAL MINES IN DISTRICT) REACH DEPTH OF 735 FT. WITH AT LEAST 2700 TO 3000 FT. OF DRIFTS AND CROSSCUTS. OLD MATTE SMELTER OPERATED AT MAMMOTH-GOOD HOPE. PRESENT ACTIVE WORKINGS CONSIST OF HEAP LEACHING PAD USING PYRITIC DUMP ORE.

Comments on development

  • MAMMOTH-GOOD HOPE AND VULCAN MINES ARE PRINCIPAL MINES IN DISTRICT, HAVING PRODUCED FROM 1898 TO 1904 AND INTERMITTENTLY THROUGH 1930 AND MOST RECENTLY BEGINNING IN 1983. INITIAL PROSPECTING WAS IN AU-BEARING GOSSAN OUTCROPS. LENS OF SE-BEARING SULFUR WAS DEVELOPED (PRESUMABLY WITH SMALL PRODUCTION) IN 1907, 1917, AND 1918. A 40-TON CAPACITY MATTE SMELTER WAS CONSTRUCTED AT MAMMOTH-GOOD HOPE AND VULCAN MINES IN 1916 AND TREATED ORE FOR SHORT TIME. FROM 1916 TO 1926, GOOD HOPE MINE AS OWNED BY GOOD HOPE MINING AND REDUCTION CO., WHOSE PRINCIPAL WAS ONE DR. WEISS (PRESUMABLY FOR WHOM THE TELLURIDE WEISSITE WAS NAMED). VULCAN PROPERTY WAS OWNED BY J.H. HIMEBAUGH. IN 1928 VULCAN, GOOD HOPE, AND OTHER CLAIMS WERE CONSOLIDATED AND OPERATED BY VULCAN CONSOLIDATED MINES CORP., WITH ITS LAST PRODUCTION REPORTED IN 1930. FOLLOWING DISCOVERY OF THORIUM IN LATE 1940S, AREA SAW CONSIDERABLE EXPLORATION IN 1950S, BUT NO TH ORE WAS PRODUCED. DIAMOND C MINING AND MILLING CO. OF GUNNISON CONTROLLED MAMMOTH-GOOD HOPE PROPERTY IN 1937. IN EARLY 1950S, NEWMONT MINING CONDUCTED CU-ZN EXPLORATION BY GEOPHYSICAL SURVEYS AND CORE DRILLING. IN 1962, OSCEOLA MINING CO. STAKED SEVERAL CLAIMS, BUT ITS EXPLORATION ACTIVITIES WERE UNKNOWN. IN 1974-1975, NORANDA EXPLORATION OPTIONED AVAILABLE CLAIMS AND CONDUCTED GEOLOGIC MAPPING, VLF-EM AND MAGNETIC SURVEYING, AND DRILLED TWO CORE HOLES. BEGINNING IN 1983, WEBBCO (VULCAN RESOURCES) BEGAN RECOVERY OF AU VIA CYANIDE HEAP-LEACH PAD OPERATION AT MAMMOTH-GOOD HOPE. FAIRLY HOMOGENEOUS DUMP ORE CONSISTING OF VERY FINE-GRAINED AURIFEROUS PYRITE AND CONTAINING ABOUT 0.1 OZ/TON AU IS PELLETIZED, MIXED WITH SLAKED LIME, AND LEACHED ON ASPHALT-LINED PAD, WITH 65 TO 70 % RECOVERY.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS D011132

Bibliographic references

  • Deposit

    DROBECK, P.A., 1981, PROTEROZOIC SYNGENETIC MASSIVE SULFIDE DEPOSITS IN THE GUNNISON GOLD BELT, COLORADO, IN EPIS, R.C., AND CALLENDER, J.F., EDS., WESTERN SLOPE COLORADO: NEW MEXICO GEOL. SOC. 32D FIELD CONF. GUIDEBOOK, P. 279-286.

  • Deposit

    HARTLEY, P.D., 1976, THE GEOLOGY AND MINERALIZATION OF A PRECAMBRIAN MASSIVE SULFIDE DEPOSIT AT VULCAN, GUNNISON COUNTY, COLORADO: STANFORD UNIV. M.SC. THESIS.

  • Deposit

    HARTLEY, P.D., 1983, GEOLOGY AND MINERALIZATION OF THE VULCAN-GOOD HOPE MASSIVE SULFIDE DEPOSIT, GUNNISON COUNTY, COLORADO, IN HANDFIELD, R.C., ED., GUNNISON GOLD BELT AND POWDERHORN CARBONATITE FIELD TRIP GUIDEBOOK: DREGS, P. 19-27.

  • Deposit

    HEDLUND, D.C., AND OLSON, J.C., 1975, GEOLOGIC MAP OF THE POWDERHORN QUADRANGLE, GUNNISON AND SAGUACHE COUNTIES, COLORADO: USGS MAP GQ-1178.

  • Deposit

    LAKES, ARTHUR, 1896, SKETCH OF A PORTION OF THE GUNNISON GOLD BELT INCLUDING THE VULCAN AND MAMMOTH CHIMNEY MINES: AIME TRANS., V. 26, P. 440-448.

  • Deposit

    OLSON, J.C., AND OTHERS, 1975, GEOLOGIC MAP OF THE SPRING HILL CREEK QUADRANGLE, SAGUACHE COUNTY, COLORADO: USGS MAP MF-713.

  • Deposit

    SHERIDAN, D.M., AND OTHERS, 1981, PRECAMBRIAN SULFIDE DEPOSITS IN THE GUNNISON REGION, COLORADO, IN EPIS, R.C., AND CALLENDER, J.F., EDS., WESTERN SLOPE COLORADO: NEW MEXICO GEOL. SOC. 32D FIELD CONF. GUIDEBOOK, P. 273-277.

  • Deposit

    CAMERON, E.N., AND THREADGOLD, I.M., 1961, VULCANITE, A NEW COPPER TELLURIDE FROM COLORADO: AM. MINERALOGIST, V. 46, P. 258-268.

  • Deposit

    COLORADO DIV. MINES INF. REPTS. AND ANNUAL OPERATOR REPTS.

  • Deposit

    BLM MINERAL SURVEYS MS 10909, 10910, 11243, 12175, 12454, 12456, 13156, 13179, 16392, 17390, 19038, 199920

General comments

Subject category Comment text
Deposit COUNTRY ROCK CONSISTS OF FELSIC VOLCANICS (RHYOLITE TUFFS AND RHYOLITIC LAPILLI TUFFS) METAMORPHOSED TO QUARTZOFELDSPATHIC SCHIST. AS RESULT OF HYDROTHERMAL ACTIVITY IN AND NEXT TO MINERALIZED ZONE, SCHISTS HAVE BEEN SERICITIZED, LOCALLY CHLORITIC. FOLIATION IS GENERALLY PARALLEL TO SUBPARALLEL TO BEDDING AND TRENDS EAST-WEST, DIPPING 75 TO 90 NORTH. FELSIC SEQUENCE IS BRACKETED BY THICK BASALTIC ANDESITE FLOWS METAMORPHOSED TO AMPHIBOLITE FACIES. SEQUENCE CONTAINS SEVERAL THIN, DISCONTINUOUS MAGNETITE-BEARING QUARTZITE (METACHERT) BEDS, MOST PROMINENT ONE MILE TO EAST AND APPROXIMATELY ALONG STRIKE OF SULFIDE MINERALIZATION. SEQUENCE IS INTRUDED GENERALLY ALONG FOLIATION BY APOPHYSIS OF TOLVAR PEAK GRANITE AND DISCORDANTLY BY TRACHYTE/TRACHYTE PORPHYRY DIKES. DRILLING NEAR ORE HORIZON INTERSECTED CARBONATITE DIKES (RELATED TO IRON HILL ALKALIC COMPLEX) THAT WERE NOT EXPOSED ON SURFACE. MAGNETIC ANOMALY 0.5 MILE NW OF MINE SUGGESTS POSSIBLE BURIED PYROXENITE PLUG. THREE TYPES OF MINERALIZATION: (1) STRATIFORM MASSIVE SULFIDE LENS; (2) AU-, AG-, AND CU-TELLURIDE-BEARING CRYPTOCRYSTALLINE SILICA VEIN SYSTEM CONFINED PRIMARILY TO HANGING WALL OF SULFIDE LENS; (3) NATIVE SULFUR/NATIVE SELENIUM LENS ABOUT PRESENT WATER TABLE. MASSIVE SULFIDE LENS TRENDS EAST-WEST, DIPS 80 TO 90 NORTH, AND IS ABOUT 700 FT LONG (ALONG STRIKE), 500 FT DEEP, AND AVERAGES 15 FT THICK; CONSISTS OF STRATIFORM ZONE OF BANDED, RECRYSTALLIZED COARSE-GRAINED PYRITE, SPHALERITE, AND CHALCOPYRITE WITH VARIABLE AMOUNTS OF QUARTZ AND SERICITE. LENS PINCHES OUT DOWNWARD INTO LOW-SULFIDE PYRITIC SERICITIC SCHIST. PETZITE AND SYLVANITE OCCUR AS DISSEMINATED GRAINS IN ZONE OF CRYPTOCRYSTALLINE SILICA (CHALCEDONY AND OPAL) IN QUARTZ-SERICITE SCHIST IN HANGING WALL OF MASSIVE SULFIDE LENS. CHALCEDONY VEINLETS ALSO OBSERVED CUTTING S/SE LENS AND OVERLYING GOSSAN. VEINLETS ALSO CONTAIN NATIVE TE CRYSTALS; TELLURITE, COLORADOITE, TETRADYMITE(?), AND RARE CU TELLURIDES (RICKARDITE, WEISSITE, AND VULCANITE). VEINLETS ARE UNMETAMORPHOSED AND SHOW DELICATE REPLACEMENT TEXTURES. IN OXIDIZED ZONE ABOVE SULFIDES IS HORIZONTAL, ROD-SHAPED LENS OF NATIVE SULFUR, CONTAINING SELENIUM, AND MEASURING 600 FT LONG, 20 FT THICK, AND 20 TO 30 FT WIDE. LENS LIES ABOVE WATER TABLE IN OXIDIZED SECTION OF MASSIVE SULFIDE LENS. BELOW WATER TABLE, SILICA MATRIX HAS BEEN LEACHED TO FORM ZONE OF LOOSE, FLOWING SANDLIKE PYRITE. LENS AVERAGES 78 % S AND 0.59 % SE, WITH SUBLENSES CONTAINING UP TO 17 % % SE. GOSSAN CAP DEVELOPED FROM TOP OF LENS TO SURFACE. DEPOSIT WAS ORIGINALLY BELIEVED TO BE VEIN AND CHIMNEY DEPOSIT, WITH NATIVE S RESULTING EITHER BY DOWNWARD DESULFURIZATION OR OXIDATION OF PYRITE OR BY PRECIPITATION FROM LATE-STAGE ASCENDING SULFURATED HYDROGEN GASES. NEWER INTERPRETATION OF SULFIDES IN GUNNISON GOLD BELT SHOWS MASSIVE SULFIDE TO BE SYNGENETIC, SUBMARINE, VOLCANOGENIC EXHALITE. DISTAL ORIGIN OF LENS SUGGESTED BY (1) ENCLOSURE WITHIN VOLCANICS DEPOSITED AT CONSIDERABLE DISTANCE FROM SOURCE AREA;
Deposit (2) ABSENCE OF WELL-DEFINED FEEDER OR STRATABOUND STRINGER SYSTEM; (3) ZN-RICH NATURE OF LENS. HARTLEY (1983) POSTULATED SECOND, LATER PHASE OF MINERALIZATION IN WHICH AU AND AG IN CHALCEDONIC VEIN SYSTEM SERE RECONCENTRATED FROM PRECIOUS-METAL EXHALITE HORIZON AND INTRODUCED CONTEMPORANEOUSLY WITHIN DEVELOPMENT OF GOSSAN AND S/SE LENS. MINERALIZING SOLUTIONS OF POSSIBLE MIOCENE AGE (SIMILAR IN AGE TO MINERALIZATION IN SAN JUAN MTNS) WOULD HAVE FOLLOWED STRUCTURAL DISCONTINUITY (MASSIVE SULFIDE-METAVOLCANIC CONTACT) ALONG WHICH SULFIDES COULD PRECIPITATE TELLURIDES. THIS HOT SPRING STYLE OVERPRINT ON MASSIVE SULFIDES MAY HAVE AIDED IN CREATING FAVORABLE GEOCHEMICAL CONDITIONS FOR OXIDATION OF SULFIDE TO NATIVE S. SOURCE OF SE, TE, AU, AG, AND CU IN PRECIOUS-METAL VEIN ZONE IS PROBABLY THE MASIVE SULFIDE LENS, ALTHOUGH CARBONATITES INTERSECTED IN SUBSURFACE MAY HAVE INTRODUCED THE SE-TE OVERPRINT. DROBECK (1979) PROPOSED PROTEROZOIC SYNGENETIC FUMAROLIC ORIGIN OF SULFIDE LENS. EPIGENETIC MINERALIZATION PROBABLY CREATED BY SYSTEM OF CONVECTING HOT FLUIDS (ALONG CONTACT BETWEEN SULFIDE LENS AND HOST ROCK) THAT REDISTRIBUTED TRACE ELEMENTS AND PRODUCED ZONES OF INTENSE ALTERATION. DROBECK SHOWED THAT VULCAN DEPOSIT COULD FIT INTO CUPOLA PRE-INTRUSIVE LEVEL OF DEEPER PORPHYRY INTRUSION OF POSSIBLE OLIGOCENE-MIOCENE AGE. TRACHYTE DIKES IN THIS AREA ARE OF FOUR ENVIRONMENTS OF TH OCCURRENCE KNOWN IN POWDERHORN-IORN HILL AREA AND ARE PROBABLY RELATED TO EMPLACEMENT OF LATE PRECAMBRIAN SYENITES NORTH AND WEST OF IRON HILL AND OF YOUNGER LATE PRECAMBRIAN OR CAMBRIAN CARBONATITES AT IRON HILL. DIKES FOLLOW LOCAL JOINTING IN FELSITE AND GRANITE AND ARE COMPOSED OF LATH-SHAPED ORTHOCLASE PHENOCRYSTS IN TRACHYTIC, APHANOTIC GROUNDMASS OF ORTHOCLASE MICROLITES. RADIOACTIVITY IS CONCENTRATED IN HEMATITE PSEUDOMORPHS AFTER PYRITE.
Deposit DISTRICT HAS BEEN KNOWN BY POPULAR NAME OF "VULCAN" BUT BLM CLAIM RECORDS ASSIGN DISTRICT NAME OF "DOMINGO." INDIVIDUAL RECORDS PREPARED FOR DISTRICT'S PRINCIPAL MINE (MAMMOTH-GOOD HOPE) AND FOR KNOWN THORIUM PROSPECT (SUNSET CLAIMS). ADDITIONAL REFERENCES: (11) BARGE, E.M., 1971, GEOLOGICAL REPORT--VULCAN DEPOSIT, GUNNISON COUNTY, COLORADO: UNPUB. REPT.; (12) CRAWFORD, E.P., 1927, SELENIUM DEPOSITS AT VULCAN: UNPUB. NOTES; (13) CRAWFORD, W.P., AND JOHNSON, F., 1922, GEOLOGY AND CYANIDATION OF ORE FROM THE GOOD HOPE MINE, VULCAN, COLORADO: COLORADO SCHOOL OF MINES M.SC. THESIS T-477; (14) DROBECK, P.A., 1979, GEOLOGY AND TRACE ELEMENT GEOCHEMISTRY OF A PART OF THE GUNNISON GOLD BELT, COLORADO SCHOOL OF MINES M.SC. THESIS T-2251; (15) HEDLUND, D.C., AND OLSON, J.C., 1961, FOUR ENVIRONMENTS OF THORIUM-, NIOBIUM-, AND RARE-EARTH-BEARING MINERALS IN THE POWDERHORN DISTRICT OF SOUTHWESTERN COLORADO: USGS PROF. PAPER 424-B, P. B283-B286; (16) LAKES, ARTHUR, 1898, ORES OF THE VULCAN MINE: MINES AND MINERALS, V. 18, P.562-563; (17) NELSON, A.P., (NO DATE), MINING DISTRICTS, PRODUCTING MINES AND PROSPECTIVE PROPERTIES (OF GUNNISON COUNTY): COLORADO STATE PLANNING COMM. UNPIB. REPT., P.5; (18) NELSON-MOORE, J.L., AND OTHERS, 1978, RADIOACTIVE MINERAL OCCURENCES OF COLORADO AND BIBLIOGRAPHY: CGS BULL/ 40, P.176; (19) RICKARD, T.A., 1903, ACROSS THE SAN JUAN MOUNTAINS: ENG. MINING JOUR., V.76, P. 387; (20)SHARPS, T.L., 1965, SULFUR DEPOSITS OF COLORADO; COLORADO SCHOOL OF MINES MINERAL INDUSTRIES BULL., V. 8, NO. 6; (21) TROST, P.B., 1975, GEOLOGIC REPORT ON THE VULCAN-ANACONDA-HEADLIGHT MINE AREA, DUBOIS GREENSTONE, GUNNISON COUNTY, COLORADO: UNPIB. REPT. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT; 3 FIELD OBSERV

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JAN-1984 Schwochow, Stephen D. Colorado Geological Survey