Aspen District

The Aspen District is a silver, lead, and zinc mine located in Pitkin county, Colorado at an elevation of 8,799 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Aspen District
Secondary: Roaring Fork District

Commodity

Primary: Silver
Primary: Lead
Primary: Zinc
Secondary: Copper
Secondary: Gold
Tertiary: Manganese
Tertiary: Cadmium
Tertiary: Uranium
Tertiary: Arsenic
Tertiary: Antimony
Tertiary: Platinum

Location

State: Colorado
County: Pitkin
District: Aspen (Roaring Fork) District

Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

Holdings

Not available

Workings

Type: Underground

Ownership

Not available

Production

Not available

Deposit

Record Type: District
Operation Category: Past Producer
Operation Type: Unknown
Year First Production: 1882
Year Last Production: 1968
Discovery Year: 1879
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: Y
Deposit Size: S

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

Mineral Deposit Model

Model Name: Polymetallic replacement

Orebody

Form: IRREGULAR

Form: IRREGULAR

Form: IRREGULAR

Structure

Type: R
Description: Sawatch Uplift, Central Colorado Trough, Piceance Basin, White River Uplift, Elk Uplift

Type: L
Description: Aspen Mountain Syncline, Castle Creek Fault Zone, Silver Fault, Contact Fault, Aspen Mountain Fault System, Della Fault System, Tourtellotte Park Fault System, Butte Fault System, Lenado Fault

Alterations

Alteration Type: L
Alteration Text: See Comments

Rocks

Name: Diorite
Role: Associated
Age Type: Associated Rock
Age Young: Oligocene

Analytical Data

Analytical Data: 9200, 51.3, 10.4, NR, 3.5, 5.5, 6.2, 21.4, 19.8
Analytical Data: 9000, 26.5, 4.5, 0.7, 0.4, 1.3, 4.5, 23.8, 10.3
Analytical Data: 8800, 36.5, 10.8, 1.8, 1.3, 11.9, 6.4, 23.5, 17.1
Analytical Data: 10800, 36.7, 6.0, 1.0, TRACE, 31.0, 4.4, 12.8, 28.5
Analytical Data: 7600, 234.6, 5.6, 2.6, 2.6, 13.3, 2.7, 17.3, 19.7
Analytical Data: SPURR'S (1898) AVERAGES OF ABOUT 400 ORE-SHIPMENT ASSAYS ARRANGED BY 200-FT ELEVATION INTERVALS. VALUES FOR EACH LEVEL REPRESENT ORES FROM INTERVAL +/- 100 FT OF ELEVATION. EACH SET OF VALUES IS ELEVATION (FT), OZ/TON AG, % PB, % S, % ZN, % BARITE, % FE203, % CAO, % SIO2 (NR=NOT REPORTED): 7400, 460.0, 17.5, NR, 2.4, 12.6, 1.8, 13.1, 23.2
Analytical Data: 9800, 71.9, 0.8, 2.1, 1.4, 23.2, 6.5, 10.8, 32.8
Analytical Data: 9600, 49.8, 2.9, 3.5, 1.9, 23.7, 10.1, 8.7, 22.6
Analytical Data: 9400, 26.0, 3.0, 5.7, 3.7, 7.8, 6.4, 12.7, 33.1
Analytical Data: 10000, 51.0, 4.4, 0.8, 2.1, 24.2, 8.9, 11.1, 23.0
Analytical Data: 10600, 27.3, NR, NR, NR, 30.5, NR, NR, 52.5
Analytical Data: 10400, 62.5, 6.7, 6.6, 3.2, 21.8, 10.3, 7.5, 27.3
Analytical Data: 10200, 35.6, 2, 0.9, 1.5, 16.4, 4.9, 14.8, 37.6
Analytical Data: 8600, 52.0, 2.4, 3.0, 1.0, 2.0, 3.3, 28.3, 12.8
Analytical Data: 8400, 25.3, 3.8, 1.0, 1.5, 3.5, 2.4, 28.4, 10.1
Analytical Data: 8200, 56.6, 2.1, 5.2, 3.2, 14.5, 4.5, 10.3, 9.9
Analytical Data: 8000, 59.3, 1.8, 5.2, 1.8, 25.6, 5.5, 17.5, 17.4
Analytical Data: 7800, 39.5, 16.3, 3.5, 1.9, 20.8, 4.3, 13.2, 9.2

Materials

Ore: Argentite
Ore: Pyrite
Ore: Chalcocite
Ore: Wurtzite
Ore: Smithsonite
Ore: Hemimorphite
Ore: Tenorite
Ore: Cuprite
Ore: Malachite
Ore: Chrysocolla
Ore: Bornite
Ore: Chalcopyrite
Ore: Polybasite
Ore: Anglesite
Ore: Pyrargyrite
Ore: Covellite
Ore: Sphalerite
Ore: Tetrahedrite
Gangue: Epsomite
Gangue: Selenite
Gangue: Wad
Gangue: Limonite
Gangue: Hematite
Gangue: Calcite
Gangue: Quartz
Gangue: Dolomite
Gangue: Barite
Gangue: Siderite

Comments

Comment (Location): ASPEN DISTRICT PROPER LIES FROM 1.5 MILES NE OF TOWN (TO HUNTER CREEK) ACROSS ROARING FORK RIVER TO TOURTELLOTTE PARK 2.5 MILES SOUTH OF TOWN. ON BASIS OF STRATIGRAPHIC/STRUCTURAL CONTINUITY AND SIMILARITY OF ORE OCCURRENCE, TOTAL ASPEN DISTRICT INCLUDES SUBDISTRICTS, SATELLITE DISTRICTS, OR AREAS OF LENADO (ON WOODY CREEK) AND RICHMOND HILL (SOUTH OF TOURTELLOTTE PARK). S-T-R DESIGNATIONS BASED ON MINING CLAIMS MAPS AND ON PROJECTIONS INTO UNSURVEYED AREA AROUND ASPEN. DISTRICT ALSO INCLUDES T9S, R84W (SECS. 03, 10, 15, 22, 27, 28, 33, 34) (LENADO AREA) AND EXTENDS ONTO HAYDEN PEAK AND RUEDI QUADRANGLES. LAT-LONG GIVEN IS CENTER OF COMMON LINE OF T10S, R 84 & 85W. ; INFO FROM LAND.ST :(1980)

Comment (Geology): SEQUENCE OF STRUCTURAL DEFORMATION INTERPRETED AS (OLDEST TO YOUNGEST): 1) INITIAL UNFOLDING OF SAWATCH RANGE; 2) PROBABLE CONTEMPORANEOUS BEDDING PLANE FAULTS IN LEADVILLE LIMESTONE (SILVER AND CONTACT FAULTS); 3) START OF NORTH-SOUTH-TRENDING FAULT SYSTEMS, BEGINNING WITH CASTLE CREEK FAULT ZONE (INCLUDING CASTLE CREEK, ANNIE, AND DUBUQUE FAULTS); 4) AFTER THIS OR AT SAME TIME CAME DOMAL FOLDING IN TOURTELLOTTE PARK AREA AND FORMATION OF ASSOCIATED NORTH-SOUTH AND EAST-WEST FRACTURING; 5) FORMATION OF ASPEN MOUNTAIN FAULT SYSTEM (NORTH-SOUTH TRENDS, INCLUDING PRIDE, SADDLE ROCK, SARA JANE, SCHILLER, AND MARY B. FAULTS), MINOR CROSS-FAULTING (EAST-WEST TRENDS, INCLUDING BONNYBEL AND CHLORIDE FAULTS), DELLA FAULT SYSTEM (EAST-WEST); 6) FORMATION OF TOURTELLOTTE PARK FAULT SYSTEM (NORTH-SOUTH TRENDS, INCLUDING JUSTICE, COPPER, AND ONTARIO FAULTS); 7) FORMATION OF BUTTE FAULT SYSTEM (EAST-WEST TRENDS, INCLUDING BUTTE, GOOD THUNDER, HALLET, DIXON, SILVER BELL, BURRO, GRAND DUKE, AND

Comment (Development): TUNNEL, TENCHING IN ANNIE BASIN, AND CORE DRILLING IN LENADO AREA. SMUGGLER MINE CURRENTLY (1982) UNDER LEASE. DISTRICT IS NOTED AS ONE OF FIRST TO USE ELECTRIC HOISTS AND PUMPS AND AS FIRST COLORADO DISTRICT TO PRODUCE ZN FROM OXIDIZED ORE. IN 1894, SMUGGLER MINE YIELDED AG NUGGET WEIGHING 1840 LB.

Comment (Deposit): HENRICH, CARL, 1889, NOTES ON THE GEOLOGY AND ON SOME OF THE MINES OF ASPEN MOUNTAIN, PITKIN COUNTY, COLORADO: AIME TRANS., V. 17, P. 156-206. DETAILED RECORDS COMPLETED FOR FOLLOWING PRINCIPAL MINES: ARGENTUM-JUNIATA, ASPEN, ASPEN CONTACT, ASPEN MINING AND DRAINAGE TUNNEL, AE ASPEN MINING AND SMELTING CO., BEST FRIEND, BONNYBEL, BUSHWHACKER, CAMP BIRD, CELESTE, DELLA S., DUBUQUE TUNNEL, DURANT, HIGHLAND TUNNEL, HOPE, IOWA CHIEF, JUSTIC, LAST DOLLAR, LATE ACQUISTION, LEADVILLE, LITTLE ANNIE, LITTLE PERCY, MARY B., MIDNIGHT, MOLLIE GIBSON, NEWMAN TUNNEL, PARK REGENT, PARK TUNNEL, PRIDE OF ASPEN, PRINCESS LOUISE, SCHILLER, SMUGGLER, TILLY. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Comment (Deposit): NORTH-SUTH-TRENDING ASPEN MTN AND TOURTELLOTTE PARK FAULT SYSTEMS AND BY EAST-WEST-TRENDING BUTTE FAULT SYSTEM. FARTHER SOUTH IN ANNIE BASIN-RICHMOND HILL AREA, MINERALIZED FAULT BRECCIA ASSOCIATED WITH QUARTZ PORPHYRY SILL IN BELDEN IN STEEP FAULT CONTACT AGAINST PRECAMBRIAN QUARTZ MONZONITE AND CAMBRIAN-MISSISSIPPIAN SECTION ALONG EAST MARGIN OF CASTLE CREEK FAULT ZONE. MINOR AMOUNTS OF ORE FOUND IN PRECAMBRIAN AND OLDER PALEOZOIC SEDIMENTARY ROCKS AND IN PENNSYLVANIAN MAROON FM IN AREA. ORE OCCURS AS PODS, IRREGULAR MASSES, BRECCIA CEMENT, AND VUG FILLINGS. MINERALIZATION BELIEVED TO BE LIMITED TO ONE BRIEF PERIOD COMPARED TO DURATION OF FAULTING. FOUR-STAGE PARAGENESIS INTERPRETED AS 1) EARLY PRIMARY BARITE, 2) TETRAHEDRITE, TENNANTITE, POLYBASITE (PEARCEITE), SOME CONTEMPORANEOUS BARITE, 3) FINELY CRYSTALLINE GALENA, SUBORDINATE SPHALERITE (THE MILLING ORES), 4) OXIDATION TO NATIVE AG. BASTIN (1924) CLASSIFIES EARLY PRIMARY BARITE, TENNANTITE, RARE PYRITE, AND LATER PRIMARY

Comment (Deposit): GALENA-SPHALERITE-CHALCOPYRITE, BORNTE, PEARCEITE, AND ARGENTITE ALL AS HYPOGENE; NATIVE AG, SOME PEARCEITE AND ARGENTITE(?), AND RARE CHALCOCITE AND COVELLITE AS SUPERGENE.

Comment (Workings): PRINCIPAL MINES DEVELOPED BY VERTICAL SHAFTS WITH CROSSCUTS TO SILVER AND CONTACT FAULTS. SOME DECLINES ALONG FAULT PLANES. LEVELS DEVELOPED NORTH-SOUTH AND NE-SW ALONG FAULTS. CONSIDERABLE INTERCONNECTING BETWEEN PROPERTIES. LONGER DRAINAGE AND DEVELOPMENT TUNNELS DRIVEN EASTWARD TO SOUTHWARD INTO HILLSIDES WEST, NW, AND BELOW SHAFT SITES

Comment (Development): PROSPECTORS MOVED WESTWARD FROM LEADVILLE AND MADE FIRST DISCOVERIES AROUND ASPEN IN 1879, STAKING THE SMUGGLER, DURANT, IRON, SPAR, MONARCH, AND LATE ACQUISITION CLAIMS. FIRST PRODUCTION CAME IN EARLY 1880'S FROM SPAR AND CHLORIDE MINES ON ASPEN MTN. ALTHOUGH RICH DEEPER ORES WERE FOUND BY 1884, SIGNIFICANT DEVELOPMENT NOT SEEN UNTIL ARRIVAL OF COLORADO MIDLAND RR. IN 1887. ACTIVITY ALSO SLOWED IN MID 1880'S BY LITIGATION REGARDING APEX VS VERTICAL SIDELINE METHODS OF GRANTING MINING CLAIM TITLES. DECISIONS FAVORED APEX CLAIMANTS. BOOM PERIOD FOR AG PRODUCTION WAS 1888-1892, BUT RICH ORE DEPLETION AND AG DEVALUATION IN 1893 CAUSED SUDDEN, THEN GRADUAL DECLINE TO 1903. THEN RECOVERY OF AG-BEARING ZN ORES BEGAN. BOOM IN ZN ENDED BY 1908, BUT OXIDIZED ZN AND ZN-PB ORES WERE PRODUCED SPORADICALLY FROM 1911-1929 AND 1934-1952. VERY LITTLE AG-PB-ZN PRODUCED SINCE 1952. MOST RECENT ACTIVITY WAS 1960'S AND INCLUDED ATTEMPT TO MILL SMUGGLER/MOLLIE GIBSON DUMP ORES, EXTENSION OF HIGHLAND

Comment (Geology): WINNIE FAULTS). STAGES 6 AND 7 ARE POST-MINERAL. ALTHO NO DIRECT AGES HAVE BEEN DETERMINED ON ASPEN ORES, THEIR SPATIAL ASSOCIATION SUGGESTS LARAMIDE AGE. AGES CAN BE BRACKETED BY THOSE DETERMINED ON ASSOCIATED IGNEOUS ROCKS, THE CRETACEOUS-PALEOCENE QUARTZ PORPHYRY AND APLITE (72.2 +/- 2.2 TO 67.4 +/- 2.2) AND THE LATER OLIGOCENE GRANODIORITE (33.9 +/- 1.0).

Comment (Commodity): BASTIN (1925) REPORTED OCCURRENCE OF PYRITE, CHALCOCITE, AND COVELLITE AS RARE. MOST AU IN DISTRICT APPARENTLY OCCURRED IN PLACERS; IN LODE DEPOSITS, OCCURRENCE AS NATIVE AU OR CONTAINMENT IN OTHER SULFIDES IS UNKNOWN. SB AND AS CONTAINED IN TETRAHEDRITE-TENNANTITE AND POLYBASITE-PEARCEITE. CD ASSOCIATED WITH ZINC PROBABLY IN SPHALERITE (BRYANT, 1979), BUT SPURR (1898) REPORTS OCCURRENCE OF SMALL AMOUNTS OF CD, AS, PB, ZN, CU, CO, AND NI IN PYRITE. VOLIN AND HILD (1950) REPORT OCCURRENCE OF WURTZITE IN SMUGGLER MINE.

Comment (Production): PARTIAL PRODUCTION RECORD; FIGURES PRIOR TO 1932 NOT REPORTED SEPARATELY BY DISTRICT WITHIN PITKIN COUNTY. NO PRODUCTION REPORTED FOR 1955 OR AFTER 1956.

Comment (Deposit): ADDITIONAL LITERATURE REFERENCES PERTINENT TO ASPEN DISTRICT INCLUDE--HEYL, A.V., 1964, OXIDIZED ZINC DEPOSITS OF THE UNITED STATES, PART 3--COLORADO: USGS BULL. 1135-C; MCCARTHY, J.H., JR., AND GOTT, G.B., 1966, THE DISTRIBUTION OF AG, PB, ZN, SB, AS, AND HG IN SOILS AT LENADO, ASPEN QUADRANGLE, COLORADO, WITH A PRELIMINARY GEOLOGIC MAP OF THE LENADO MINING DISTRICT, PITKIN COUNTY, COLORADO, BY BRUCE BRYANT: USGS OPEN-FILE REPT.; ROHLFING, D.P., 1938, THE COLORADO MINERAL BELT AND THE ASPEN MINING DISTRICT, PITKIN COUNTY, COLORADO: COLORADO MINING ASSOC. 1937 MINING YEAR BOOK, P. 16-17, 62-64, 90.; SPURR, J.E., 1909, ORE DEPOSITION AT ASPEN,COLORADO: ECON. GEOLOGY, V. 4, P. 310-320.; VANDERWILT, J.W., 1935, REVISION OF THE STRUCTURE AND STRATIGRAPHY OF THE ASPEN DISTRICT, COLORADO, AND ITS BEARING ON THE ORE DEPOSITS: ECON. GEOLOGY, V. 30, NO. 3, P. 223-241.; VOLIN, M.E., AND HILD, J.H., 1850, INVESTIGATION OF SMUGGLER LEAD-ZINC MINE, ASPEN, PITKIN COUNTY, COLORADO: USBM RI 4696.;

Comment (Reserve-Resource): AG-PB-ZN RESERVES VERY LIKELY REMAIN IN A NUMBER OF MINES IN THE DISTRICT, BUT THEIR REOPENING AND OPERATION IS PROBABLY SEVERELY LIMITED IN MOST PLACES BY PRESENT EXTENT OF RECREATIONAL FACILITIES. HEYL (1964) STATES THAT VERY LARGE QUANTITIES OF AG-BEARING OXIDIZED ZN-PB ORES REMAIN IN DISTRICT BECAUSE AFTER RICHER ORES WERE MINED OUT BY SELECTIVE AND IRREGULAR STOPING (AS IN SMUGGLER, MOLLIE GIBSON, AND GREAT WESTERN MINES), LEANER MATERIALS WERE WASTED ONTO DUMPS. REMAINING LARGE DUMPS CONTAIN ESTIMATED 1 TO 3 % COMBINED ZN-PB, 1 TO 4 OZ/TON AG, SOME MN, MUCH IN FORM OF OXIDIZED ORE. A FEW RICHER DUMPS, PROBABLY EXCEEDING 500,000 TONS, CONTAIN ESTIMATED 5 % COMBINED PB-ZN AND 1 TO 5 OZ/TON AG. AS OF 1056, A FEW SMALL REMAINING RICH DUMPS CONTAINED 8 TO 19 % COMBINED ZN AND PB. TOURTELLOTTE PARK MAY CONTAIN A LARGE TONNAGE OF LEAN ZN-BEARING MANGANIFEROUS DOLOMITE AND MN OXIDES.

Comment (Deposit): PRINCIPAL PRODUCTIVE ORES OCCUR ALONG CONTACT AND SILVER FAULTS, WHICH WERE INTERPRETED AS BEDDING PLANE FAULTS SEPARATING THE WEST- TO NW-DIPPING LOWER DOLOMITE (REDCLIFF) AND UPPER BLUE LIMESTONE (CASTLE CREEK) MEMBERS OF THE LEADVILLE LIMESTONE AND SEPARATING THE CASTLE CREEK MEMBER FROM OVERLYING BELDEN FM., RESPECTIVELY. MORE RECENT INTERPRETATION ASSERTS THAT BRECCIA ZONES ORIGINALLY SEEN AT THESE HORIZONS ARE ACTUALLY SOIL RUBBLE OR PALEOKARST (SOLUTION COLLAPSE AND FILLING) ZONES, ALTHO BRYANT DID NOTE SOME EVIDENCE OF MOVEMENT ON THESE PLANES AT ASPEN. STRATIGRAPHIC AND STRUCTURAL CONTROL BY KARSTIFICATION AND FAULT MOVEMENT PROVIDED FAVORABLE SITES FOR MINERALIZING SOLUTIONS RICH IN AG-PB AND SECONDARILY IN ZN AND CU, ESPECIALLY WHERE SILVER AND CONTACT FAULTS ARE CUT BY CROSS FAULTING, SUCH AS DELLA AND LENADO SYSTEMS. IN ASPEN MTN-TOURTELLOTTE PARK AREA, ORES ALSO FOUND ASSOCIATED WITH APLITE PORPHYRY SILL IN BELDEN FM ALONG TROUGH OF ASPEN MTN SYNCLINE, COMPLICATED BY

References

Reference (Deposit): BRYANT, BRUCE, AND FREEMAN, V.L., 1977, GEOLOGIC SUMMARY OF THE ASOEN AREA, SOUTHERN ROCKY MOUNTAINS, COLORADO, IN VEAL, H.K., ED., EXPLORATION FRONTIERS OF THE CENTRAL AND SOUTHERN ROCKIES: RMAG SYMP. GUIDEBOOK, P. 441-449. &&

Reference (Deposit): DEVOTO, R.H., AND MASLYN, R.M., 1977, SEDIMENTOLOGY AND DIAGENESIS OF THE LEADVILLE FORMATION AND CONTROLS OF LEAD-ZINC-SILVER DEPOSITS, CENTRAL COLORADO: MOUNTAIN GEOLOGIST, V. 14, NO. 1, P. 27-28. & &

Reference (Deposit): HENDERSON, C.W., 1926, MINING IN COLORADO, A HISTORY OF DISCOVERY, DEVELOPMENT, AND PRODUCTION: USGS PROF. PAPER 138, P. 197-201. &&

Reference (Deposit): BASTIN, E.S., 1924, OBSERVATIONS ON THE RICH SILVER ORES OF ASPEN, COLORADO: USGS BULL. 750, P. 41-62.

Reference (Deposit): BRYANT, BRUCE, 1972, MAP SHOWING MINES, PROSPECTS, AND AREAS OF SIGNIFICANT SILVER, LEAD, AND ZINC PRODUCTION IN THE ASPEN QUADRANGLE, PITKIN COUNTY, COLORADO: USGS MAP I-785-D.

Reference (Deposit): BRYANT, BRUCE, 1971, GEOLOGIC MAP OF THE ASPEN QUADRANGLE, PITKIN COUNTY, COLORADO: USGS MAP GQ-933.

Reference (Deposit): BRYANT, BRUCE 1977, MINING AT ASPEN, IN VEAL, H.K., ED., EXPLORATION FRONTIERS OF THE CENTRAL AND SOUTHERN ROCKIES: RMAG SYMP. GUIDEBOOK, P. 451-456. & &

Reference (Deposit): BRYANT, BRUCE 1979, GEOLOGY OF THE ASPEN 15-MINUTE QUADRANGLE, PITKIN AND GUNNISON COUNTIES, COLORADO: USGS PROF. PAPER 1073, 146 P. & &

Reference (Deposit): KNOPF, ADOLPH, 1926, RECENT DEVELOPMENTS IN THE ASPEN DISTRICT, COLORADO: USGS BULL. 785, P. 1-28. & &

Reference (Deposit): SPURR, J.E., 1898, GEOLOGY OF THE ASPEN MINING DISTRICT, COLORADO: USGS MON. 260 P.

Reference (Production): VANDERWILT, J.W., 1947, MINERAL RESOURCES OF COLORADO: FIGS. FOR 1932-45; USBM MINERALS YEARBOOKS FOR REMAINING YEARS

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