Decker Mine

From Global Energy Monitor

The Decker Coal Mine was a surface mine, owned by the Decker Coal Company, a wholly-owned subsidiary of coal firm Lighthouse Resources Inc., in Montana, United States.[1]

The mine closed in 2021 after its owner, Lighthouse Resources, filed for bankruptcy.[2]


The satellite image below shows the exact location of the now-closed mine in Montana, USA.

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Decker Coal Mine was located in the northern Powder River Basin within Montana’s Big Horn County.

The mine, whose operations began in the 1970s, consisted of two mining areas—East Decker and West Decker—each with its own separate facilities. Both were managed by Kiewit Mining Group, Inc.[3] It was permitted to produce up to 12 million tons of coal per year.[3] Coal mined from Decker Coal was primarily marketed to utilities in the Midwest. The mine is serviced by BNSF Railway.[4]


Throughout the life of the mine, its ownership changed hands multiple times. As of the 2000s, it was owned by the Decker Coal Company, which at that time, was a 50-50 joint venture between Level 3 Communication and Rio Tinto Energy America (RTEA). (RTEA purchased the share held by NERCO, a PacifiCorp subsidiary in 1993.)[3]

Rio Tinto Energy America's 50% share in the joint venture was then transferred into its spin-off company Cloud Peak Energy in 2008.[3]

In January 2010, Cloud Peak Energy (CPE) announced that the Decker Coal Company had accepted a buy-out offer "from an eastern utility company for a coal supply contract originally scheduled through 2012." In an announcement CPE stated that "the customer’s contract accounted for approximately 30 percent of production for 2010 and the majority of the production for 2011 and 2012. The arrangement was mutually beneficial to both the utility and the Decker Joint Venture as it allowed the utility to avoid purchasing coal it no longer required, and Decker to pursue more favorable sales opportunities. Decker Coal Company currently holds no firm sales contracts beyond 2011, but continues to seek market opportunities for the approximately 42 million tons of non-reserve coal held by the Company."[5]

In November 2011, Australia-based Ambre Energy North America assumed the operation of, and acquired a 50% ownership interest in the Decker coal mine.[4] (In 2015, Ambre Energy changed its name to Lighthouse Resources Inc.)[6]

Cloud Peak sues Ambre Energy

In June 2011, Cloud Peak Energy signed a 10-year deal with Westshore Terminals to ship basin coal to Asia from its port in Vancouver, British Columbia. The company shipped 3.3 million tons of coal through the terminal to Asian customers in 2010.[7] However, due to their claims that the mine lost $21.1 million in 2011, Cloud Peak soon planned to close and reclaim the Decker mine after 2013.[8]

Meanwhile, Ambre Energy had signed a deal with two South Korean utilities to supply 4.4 million tons of coal a year in association with two export terminal projects it was pursuing. In response to this, Cloud Peak Energy sued Ambre Energy in July 2012. In a lawsuit filed in the U.S. District Court in Montana, the company alleged that Ambre's export plans to ship coal to Asian markets from Decker Mine were developed without Cloud Peak's approval.[8] Ambre noted that Cloud Peak, a big player in Montana and Wyoming's Powder River Basin, was a competitor as well as a business partner.[8] (Cloud Energy operates the Antelope Coal Mine, Cordero Rojo Mine, Spring Creek Mine, Decker Mine, and Jacobs Ranch Mine in the Powder River Basin.)

By December 2012, Ambre Energy offered to purchase Cloud Peak Energy’s 50% interest in the Decker mine. The agreement, which also provided for the joint resolution and dismissal of the pending Decker litigation, was completed in 2014.[9][10]


Following a decline in demand for thermal coal, Lighthouse Resources went bankrupt in December 2020 and decided to close the mine.[2] By January 2021, all but four of the mine's 130-some workers had been laid off.[11] Reclamation of the mining area was scheduled to begin that same year.[12]

Mine Data

  • Operator: Decker Coal Company
  • Owner: Lighthouse Resources Inc.[4][13]
  • Location: Next to the Tongue River Reservoir near Decker, Montana, USA
  • GPS Coordinates: 45.058724, -106.834937 (Exact)
  • Status: Closed[2]
  • Production: 6,984,546 short tons
  • Total Resource:
  • Mineable Reserves:
  • Coal Type: Subbituminous (Thermal)[3]
  • Mine Type: Surface
  • Start Year: 1970s[4]
  • Closure Year: 2021[2]

Articles and resources

Related articles


  1. Case Number: 27-CA-155559, National Labor Relations Board website, accessed May 2023.
  2. 2.0 2.1 2.2 2.3 "Lighthouse Resources Ceases Operations at Decker Coal Mine, Montana", Mining Connection, 8 February 2021.
  3. 3.0 3.1 3.2 3.3 3.4 Rio Tinto Energy America, "Decker Coal", Rio Tinto Energy America website, Archived from the original on 13 May 2011.
  4. 4.0 4.1 4.2 4.3 Ambre Energy Limited, Ambre Energy directors’ and financial report for the period 1 July 2012 to 31 December 2012, Ambre Energy Limited website, Archived from the original on 2 March 2019.
  5. Cloud Peak Energy, "Decker Coal Accepts Buy-Out of Coal Supply Contract", Media Release, January 6, 2010.
  6. George Plaven, "Ambre Energy changes name to Lighthouse Resources", East Oregonian, 13 April 2015.
  7. "Cloud Peak Energy to send more Powder River Basin coal to Asia" Jeremy Fugleberg, Star-Tribune, June 15, 2011.
  8. 8.0 8.1 8.2 "Lawsuit clouds Ambre Energy's plans to export coal from Columbia River ports" Scott Learn, The Oregonian, July 16, 2012.
  9. "Cloud Peak Energy and Ambre Energy Announcement: Ambre Energy to Purchase Remaining Decker Mine Interest from Cloud Peak Energy and Companies to Settle Decker Litigation", Business Wire, 5 December 2012.
  10. "Cloud Peak Energy and Ambre Energy Announce Completion of Ambre Energy’s Purchase of Decker Mine Interest from Cloud Peak Energy", Business Wire, 15 September 2014.
  11. "Montana coal mine closes amid decline in demand", AP News, 5 February 2021.
  12. Institute for Energy Economics and Financial Analysis, "Decker Mine in Montana Closes in Wake of Lighthouse Resources Bankruptcy", IEEFA website, Archived from the original on 20 September 2021.
  13. Stephanie Scarcliff, "GM Says Montana Mine to ‘Pick up Where it Left Off’", County 17 News, 25 May 2020.

External Articles