Boston Mine (Boston Consolidated; Esperanza), Mokelumne Hill, Mokelumne Hill Mining District, East Belt, Calaveras County, California, USAi
This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84):
38° 19' 10'' North , 120° 40' 28'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Mokelumne Hill | 646 (2011) | 3.5km |
| Jackson | 4,649 (2017) | 9.3km |
| Pine Grove | 2,219 (2011) | 10.5km |
| Martell | 282 (2011) | 11.8km |
| Red Corral | 1,413 (2017) | 11.9km |
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
Local clubs are the best way to get access to collecting localities
| Club | Location | Distance |
|---|---|---|
| Amador County Gem & Mineral Society | Sutter Creek, California | 14km |
| Calaveras Gem & Mineral Society | Angels Camp, California | 30km |
| El Dorado County Mineral and Gem Society | Placerville, California | 47km |
| Gold Country Treasure Seekers | Placerville, California | 47km |
A former Au-Pb-Zn-Cu mine located in sec. 5, T5N, R12E, MDM, about 4.65 km NE of Mokelumne Hill (town) (located along Indian Creek). The property consisted of 9 claims (3 patented and 6 unpatented). Active during the 1870's, 1892-1900, 1920-1925, 1933-1935, and from 1935 to 1937. MRDS database stated accuracy for this location is 100 meters.
Mineralization is a vein deposit hosted in schist. The ore body strikes N and dips 30-40E at a width of 15.24 meters. The vein is in rocks of the Calaveras Formation, consisting locally of limestone, schist and serpentine intruded by diorite. The vein is a crushed diorite dike and contains inclusions of the host rock schist. At the 100 foot level, the vein is 40 to 50 feet thick. At the 300 foot level the footwall is a hard, black dike with marble between it and the vein. On the hanging wall to the N there is ground-up quartz with successive layers of serpentine, limestone and black schist. Zinc and copper sulfides are present. Local rocks include Paleozoic marine rocks, undivided, unit 4 (Western Sierra Nevada).
Workings include surface and underground openings with an overall depth of 204.52 meters. In 1892 surface ore was being mined. Extensive underground mining began in 1893 and a 1,000 foot shaft was completed in 1900. The shaft is inclined with levels at the 50, 100, 200, 300, 500, 700 and 950 foot levels. Most of the ore was mined at the 150 level during later operations. No deep development was undertaken. There is also a glory hole over the 50 foot level. There are numerous crosscuts, drifts, raises, etc. A small amount of work was done with little production.
Production data are found in: Clark, Wm. B. & P.A. Lydon (1962).
The total output of the mine was estimated at $1,000,000 (period values).
The average grade of the ore was $35 ton/Au (period values), with high-grade pockets encountered.
Analytical data results: 3 to 4% auriferous iron sulfides.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Galena Formula: PbS |
| ⓘ Gold Formula: Au |
| ⓘ Pyrite Formula: FeS2 |
| ⓘ Quartz Formula: SiO2 |
| ⓘ Sphalerite Formula: ZnS Description: Referred to as "zinc sulfides" in the reference. |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Gold | 1.AA.05 | Au |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Sphalerite | 2.CB.05a | ZnS |
| ⓘ | Galena | 2.CD.10 | PbS |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Quartz | SiO2 |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| S | Sulfur | |
| S | ⓘ Galena | PbS |
| S | ⓘ Pyrite | FeS2 |
| S | ⓘ Sphalerite | ZnS |
| Fe | Iron | |
| Fe | ⓘ Pyrite | FeS2 |
| Zn | Zinc | |
| Zn | ⓘ Sphalerite | ZnS |
| Au | Gold | |
| Au | ⓘ Gold | Au |
| Pb | Lead | |
| Pb | ⓘ Galena | PbS |
Other Databases
| Link to USGS MRDS: | 10028912 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Shoofly-Olds Ferry DomainDomain
- Sierra Nevada BatholithVolcanic Arc
USA
- Sierra NevadaMountain Range
This page 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.
