Henderson

Overview

The Henderson mine is located approximately 42 miles west of Denver, Colorado, USA. The mine has been in operation since 1976.

It is an underground molybdenum mine and mill operations (4,806 ha) located near Empire, Colorado, comprising 4,792 ha of patented mining claims and other fee lands, and a 14 ha easement with the U.S. Forest Service for the surface portion of the conveyor corridor. The Henderson mill site is located approximately 15 miles west of the mine. The Henderson mine and mill are connected by a 16 km conveyor tunnel under the Continental Divide and an additional five-mile surface conveyor.

The mine has been in operation since 1976 and has produced more than 160 million tons of ore and 770 million pounds of molybdenum during the past 27 years. It is a porphyry molybdenum deposit with molybdenite as the primary sulfide mineral.

The Henderson mine is owned by Freeport McMoran Copper & Gold, the world's largest molybdenum and molybdenum chemicals producer.

Location

The Henderson molybdenum mine is located approximately 42 miles west of Denver, Colorado, USA.

The state of Colorado is part of the Southwestern United States and encompasses most of the Southern Rocky Mountains. Oil, natural gas and mining play an important role in the state's economy.

The mine is located in a mountainous region with the main access shaft at 3,180 meters above sea level. The main production levels are currently at elevations of 2,350 and 2,200 meters above sea level.  This region experiences significant snowfall during the winter months.

The Henderson mine and mill operations encompass approximately 11,878 acres comprising 11,843 acres of patented mining claims and other fee lands, and a 35 acre easement with the U.S. Forest Service for the surface portion of the conveyor corridor.

Geology & Mineralization

The Henderson deposit is a classic Climax-type porphyry molybdenum deposit with molybdenite as the primary sulfide mineral.

The deposit consists of ore shells of quartz-molybdenite stockwork veins that lie above and surrounding the apices of cupola-like, highly evolved, calc-alkaline granite and subvolcanic rhyolite-porphyry bodies.

As of December 2011, Henderson mine's reserves were estimated at 121 million tonnes grading 0.174% molybdenum.

Mining & Operation

The operation consists of an underground block-caving mine where molybdenite ore is mined and transported to a conventional sulfide mill. The Henderson mine and mill are connected by a 16 km conveyor tunnel under the Continental Divide and an additional five-mile surface conveyor.

The main production levels are currently at elevations of 2,200 and 2,350 meters above sea level.

The available underground mining equipment fleet consists of 13 nine−metric ton load−haul−dump (LHD) units and six 73−metric ton haul trucks, which deliver ore to a gyratory crusher feeding a series of three overland conveyors to the mill stockpiles.

The mine has been in operation since 1976.

Processing

The Henderson mill site is located approximately 15 miles west of the mine. The Henderson mine and mill are connected by a 16 km conveyor tunnel under the Continental Divide and an additional five-mile surface conveyor.

The concentrator is capable of operating at a rate of 40,000 tons of ore per day, producing molybdenum disulfide concentrate containing up to 58 percent molybdenum.

Most of the concentrate is shipped to Fort Madison roasting and chemical processing facility in Iowa where a number of different products are made for final sale to customers. A portion of Henderson’s production is sold to customers as molybdenum disulfide.

The mine has the capacity to produce 40 million pounds of molybdenum per year. The mine's net cash costs were $6.34 per pound of molybdenum in 2011.

Henderson operations receive electrical power through long−term contracts with Xcel Energy and natural gas through long−term contracts with Anadarko Energy Services Company, with Xcel Energy as the transporter.

Environment & Community

The Henderson Operation has been ISO certified since 1992 and the current certification is ISO 9001:2000. In 1999, the company received an Environmental Awareness Award from the United States  Forest Service for the design, engineering, construction and implementation of the 15-mile overland conveyor system. In 2005 Henderson Operation received the environmental certification ISO 14001:2004. Henderson Operations received OHSAS 18001 certification in 2007.

Consistent with the company philosophy, all locations have diligently worked on continual improvement efforts in the area of environmental management. Such efforts have focused on not only minimizing impact on the environment and complying with the myriad of environmental laws and regulations, but also have included measures to improve environmental quality. The key to these efforts has been incorporating environmental responsibilities and related activities into our day-to-day operations. Underlying all mining, milling and production operations is the belief that mineral wealth can be utilized for human progress in harmony with conservation and recreation. A tremendous amount of environmental care and attention has been expended on all of our operations