United States

Middle Tennessee Complex

Click for more information

Categories

Overview

Mine TypeUnderground
Commodities
  • Zinc
Mining Method
  • Room-and-pillar
  • Longhole stoping
Production Start... Lock
Mine Life... Lock
ShapshotMiddle Tennessee Complex is comprised of three underground zinc mines: Gordonsville, Cumberland, Elmwood, and a processing plant located at the Gordonsville mine site.

In July 2019, Nyrstar’s operating business became majority owned by Trafigura. Production numbers have not been publicly available since then.

On October 31, 2023, Nyrstar's Middle Tennessee Mines in Gordonsville, TN, announced today that it will temporarily pause production operations on 30 November 2023. This decision comes after a thorough review and is in direct response to significantly weakened market conditions and inflationary impacts on input costs and operating margins.

Production at Middle Tennessee Mines will resume as soon as it is economically viable or once the proposed gallium and germanium production capacity at Nyrstar Clarksville comes on line in the next few years.
Related Asset

Owners

SourceSource
CompanyInterestOwnership
Trafigura Group Pte Ltd. 100 % Indirect

Contractors

Lock

- subscription is required.

Deposit type

  • Mississippi Valley Type

Summary:

The MTM Project is a classic example of a Mississippi Valley Type ("MVT") Pb-Zn deposit.

Brecciation and zinc mineralization is associated with the Lower Ordovician upper Knox Group, which is the unit of interest on the MTM Project. The main members of upper Knox Group are the Mascot Dolomite and the Kingsport Formation. The Mascot Dolomite consists of predominantly very finely crystalline dolostone units of various shades of brown and gray interbedded with some limestone units or their dolomitized medium and coarsely crystalline equivalents. The very finely crystalline dolostones are considered to be primary in origin, that is, they formed very early in the history of the strata regardless of the exact dolomitization mechanism(s). The thickness of the Mascot ranges from 759 to 847 ft.

The upper Mascot includes the interval from the Knox unconformity to the M-3 marker. Thickness of this section is very variable primarily due to removal of upper units by pre-Chazyan erosion; in some areas of Central Tennessee most of the interval is missing. In Smith and Trousdale counties (the MTM Project area), the upper Mascot ranges from about 135 to 225 ft.

The upper part of the late breccia systems host the main economic zinc deposits. Sphalerite, fluorite, barite, marcasite, pyrite, calcite, dolomite, and quartz form varying proportions of the cement of the mineral-matrix breccia. Economic grade occurrences of sphalerite are not distributed uniformly throughout breccia structures, but occur along the periphery of the bodies.

Three types of sphalerite, distinguished by colour and texture, are present in the MTM deposits: massive, vug fill, and disseminated. The massive sphalerite, the dominant variety, is characterized by coarsely crystalline, dark reddishbrown, resinous masses in mineralized breccias, either as single-phase aggregates or inter-grown with gangue minerals. Vug fill sphalerite, which fills vugs of various dimensions, is characterized by large crystal size, dark brown to black colour and rubyred internal reflection. Disseminated sphalerite is yellowish-brown in colour and occurs as small grains in altered limestone and fine-grained dolostone at the periphery of breccia bodies.

Reserves

Lock

- subscription is required.

Mining Methods

Lock

- subscription is required.

Comminution

Crushers and Mills

Lock

- subscription is required.

Processing

Lock

- subscription is required.

Production

CommodityProductUnits201820172015
Zinc Metal in concentrate kt 392247
Zinc Concentrate kt 603474

Operational metrics

Metrics201820172015
Tonnes milled 1,389 kt of ore769 kt of ore1,482 kt of ore

Production Costs

Commodity production costs have not been reported.

Operating Costs

Currency20182017
Direct operating costs ($/t milled) USD 65  60  

Heavy Mobile Equipment

Lock

- subscription is required.

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Feb 28, 2024
....................... Subscription required ....................... Subscription required Subscription required Feb 28, 2024

EmployeesYear
...... Subscription required 2023
...... Subscription required 2022
...... Subscription required 2021
...... Subscription required 2020
...... Subscription required 2019
...... Subscription required 2018
...... Subscription required 2017

Aerial view:

Lock

- subscription is required.