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Modification of Molybdenum Autoclave Process (MAP) Plant:
Kennecott Utah Copper LLC

The MAP facility is currently under construction, and commissioning is expected to start in 2013. Public comment is being sought through March 11, 2013 on Kennecott’s request to modify the design of the MAP plant.

The design changes have resulted in the modification of the cooling tower. Kennecott will also add a natural gas-fired boiler, calciner, reoxidizer, two dryers, and pollution control equipment.

The MAP plant emissions, in tons per year, will change as follows:

  • PM10 will decrease by 1.23 tpy to 13.11 tpy
  • PM2.5 will decrease by 4.35 tpy to 9.99 tpy
  • SO2 will increase by 2.20 tpy to 2.43 tpy
  • NOX will increase by 7.58 tpy to 35.57 tpy
  • CO will increase by 10.29 tpy to 39.54 tpy
  • VOC will increase by 0.89 tpy to 6.71 tpy
  • HAPs will increase by 0.01 tpy to 0.36 tpy

The MAP plant is currently permitted under Approval Order (AO) DAQE-AN0103460046-10.

Process Overview

This modification to the current AO is needed to address design changes, update vendor information, update mass and energy balances, and an updated operating strategy.

In the copper ore, molybdenum is present as molybdenum disulfide (MoS2). The Copperton Concentrator produces bulk concentrate which consists of copper, molybdenum, gold, and silver, among other metals. The molybdenum concentrate is separated from the bulk concentrate using differential flotation. Currently, KUCC sends the molybdenum concentrate to foreign roasters to produce molybdenum trioxide (MoO3). KUCC has designed the MAP to convert MoS2 to MoO3, and eliminate the need to export the product. The MAP process includes oxidation, solution purification and crystallization, product drying, calcining, and packaging.

The NOI and the draft permit (ITA) are available for review online.

Comments may be submitted to:

Bryce Bird, Director
Utah Division of Air Quality
PO Box 144820
Salt Lake City, UT 84114-4820