Climax Molybdenum operates the Henderson Mine and Mill in the Rocky Mountains, west of Denver. It is the world’s largest primary producer of molybdenum and has been in operation since 1976. Henderson has the capability to produce between 30 and 40 million pounds of molybdenum per year. Separated by the Continental Divide, the Henderson Mine and Mill are connected by one of the world’s longest conveyor systems, a 10-mile elevated belt that runs underneath the Continental Divide and emerges above ground for the final five miles.

In August 2015, the Company announced revised capital and operating plans in response to the recent decline in commodity prices. At Henderson, the new plan included operating at a lower rate and reducing production by 35 percent. In October 2015, the Company initiated a plan to reduce molybdenum production at Henderson by an additional 45 percent in response to a continued weak molybdenum market.  Additionally, the Company will suspend all underground development activity in the first-quarter 2016.  This leaves a 5-year plan at a 10-million pound production rate.

In 2016, molybdenum production at Henderson amounted to 10 million pounds.

In 2017, molybdenum production amounted to 12 million pounds and over 330 people were employed here


Henderson Operations Fast Facts

  • The Henderson Mine is located in Clear Creek County on the east side of the Continental Divide, in the Rocky Mountains fifty miles west of Denver, CO
  • The Henderson Mill is located on the west side of the Continental Divide, fifteen miles from the mine, in Grand County
  • The mine and mill are connected by the world’s largest conveyor; a fifteen mile elevated belt that passes underneath the Continental Divide through an old train tunnel and then above ground to the mill


  • To view the economic impact of Freeport-McMoRan in Colorado, click here
  • To find out more about the sustainable development projects at Henderson, click here
  • Here you will find:
    • Operations consisting of a large block—cave underground mining complex feeding a concentrator with a current capacity of approximately 32,000 metric tons per day
    • Mill and mine operations encompass approximately 11,900 acres
    • The available underground mining equipment fleet consists of fourteen 9—metric ton load—haul—dump (LHD) units and six 73—metric ton haul trucks
  • The majority of molybdenum concentrate produced here is shipped to our Fort Madison, Iowa processing facility

Key Mill Statistics

Concentrate in SupersacksAt full rates, the mill will operate at 28,000 st/d. The ore will be sent to a SAG mill and then to a ball mill for grinding. In the flotation circuit, water and reagents will be added to create a slurry. The reagents will cause the particles containing molybdenum to float when the slurry is mixed with air, and this allows separation of the moly from the host rock. The worthless ground rock (tailings) is sent to the tailings dams. Recoveries are expected to average 89% for molybdenum. Final concentrate will be thickened, pumped to storage tanks, filtered and dried to be stored in day bins. The dried concentrate will be packed in supersacks and shipped by truck to offsite facilities.

  • Full rates of 28,000 st/d (short tons per day)
  • 140 people work in the mill facility
  • 89% Mo mill recovery
  • Ore contains 0.16% Mo (3 lbs Mo/st ore)
  • Final product packed in supersacks (3,850 pounds each)
  • At full rates, mill will produce 30 million pounds of molybdenum per year (over 80,000 pounds per day)