Sweetwater Mine (Milliken Mine; Frank R. Milliken; Blair Creek; Ozark Lead Company Mine; Adair Creek; Logan Creek), Ellington, Viburnum Trend District, Reynolds Co., Missouri, USA
|Latitude & Longitude (WGS84):||37° 21' 32'' North , 91° 8' 48'' West|
|Latitude & Longitude (decimal):||37.35900,-91.14689|
|Köppen climate type:||Cfa : Humid subtropical climate|
A Pb-Zn occurrence/mine located about 12 miles NW of Ellington. Formerly owned & operated by Ozark Lead Company from 1968 to 1986 (although it was not in production from 1983 - 1986 due to low lead prices). Sold to ASARCO in 1986, reopened December, 1987. Sold to the Doe Run Company in 1997, and is presently in operation.
Reserves in 1988 amounted to 22.6 million tons of ore at an average of 4.84% Pb & 0.59% Zn.
Mining Method: Room and Pillar. Drill+Blast with LHD or mine truck haulage to ore chutes below. After crushing underground, ore is hauled to a 20 foot diameter x 1,250 foot deep, central 3-compartment hoisting shaft.
Regional Geology: The Viburnum Trend is a 6 mile x 40 mile North-trending deposit discovered in the late 1950's and early 1960's whose Pb-Ag-Zn deposits are exploited by the Brushy Creek, Buick, Fletcher, Magmont, Sweetwater, West Fork, and Viburnum mines Nos. 27, 28, 29, and 35 at depths ranging from 1,000-1,450 feet.
The Viburnum Trend deposits differ from other Mississippi Valley-type lead-zinc ore deposits in that ores are shallower, they include nickel and cobalt minerals, and some copper-iron sulfides. Also, while ores were formed from hot, saline brines, it is generally accepted that for the Viburnum Trend, this was a repetitive precipitation and dissolution process for the sulfides, particularly galena and suggests that the ore-forming base metal constituents were transported with reduced sulfur in the same solutions, with precipitation initiated by a change in pH, dilution, and/or a decrease in temperature. For the Sweetwater ores, the repetitive precipitations comprised decreasing base metal concentrations in the mineralizing fluids.
Most ore minerals are found as sulfides such as galena, sphalerite, and chalcopyrite. Gangue minerals associated with the economic minerals include pyrite, calcite, dolomite, and quartz.
Sweetwater Geology: There are 8 distinct ore bodies distributed at depth within the Bonneterre formation. The Bonneterre itself comprises four facies; fore reef, reef complex, back reef, and shelf. These facies are petrographic units developed in response to sea level fluctuations and the distribution of Precambrian knobs and ridges in a shallow Cambrian sea. Oolitic and digitate stromatolite facies predominate in the mine, and stratigraphic relationships record a prograding sedimentary pattern during lower Bonneterre sedimentation that expresses as an interfingering of the planar stromatolitic burrowed lime mudstone (reef complex) facies with the digitate (back reef) facies.
24 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
470 - 485.4 Ma
Age: Early Ordovician (470 - 485.4 Ma)
Stratigraphic Name: Gasconade Dolomite
Comments: IN SOUTHEAST MO-Gasconade Dolomite- (700 ft max) coarsely crystalline cherty dolomite with basal sandstone member; Gunter Sandstone Member- (30 ft. max) quartzose sandstone. Host to barite deposits on the northwest flank of Ozark Uplift.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.