[Editor's Note: During the Chino Mine furloughs, haul trucks are not transporting ore from Hanover Mountain to Chino, but magnetite reserves are still being moved.]

A story about current mining in the Central Mining District

Story and Photos by Christopher Saxman, with assistance from Terry Humble

Freeport-McMoRan is busy 24/7 taking copper from the ground, processing it and shipping it to El Paso, Texas and Miami, Arizona. Of course copper mining in Grant County, specifically the Central Mining District, all started in the early 1800s. At that time the ore was carried on the backs of mules for hundreds of miles down into Mexico. Mining then was done under threat of Indian attack, mostly by the Apache. Understandably, they did not like all these miners digging up their grounds. The native warriors were able to bring mining to a halt several times.

Underground mining in the CMD continued off and on until the turn of the 18th century when the open pit mine was started. Once the railroad reached the mines, they became a profitable venture. Profitable, but subject to the fall in metal prices which shut down the mines several times, the most recent being in 2002 and again in 2009-2010.

FMI is now concentrating on their current mining efforts on both the Chino Pit and Hanover Mountain. This 7,525-foot-high mountain is purported to have some of the highest concentration of copper in North America. After a long and costly approval process, the company built a $60 million, 4-mile-long, 125-foot wide, haul road through the mountains from Fierro to the existing Chino pit and its operations. They also had to remove the Continental headframe and operation site along with some of the Pewabic mine site to make room for their road and operations. The road passes right by the Kerney mine, which remains, then, it goes over Hwy. 152. Once all this was complete, they began removing Hanover Mountain. In the photos note the mountain appearing behind Hanover Mountain.

Hanover Mountain 100617

Hanover Mountain 091318

Before all this Covid-19 matter, mine historian Terry Humble and I were invited to the top of Hanover Mountain to see the FMI's mining operation, and it is a massive effort there. On site, two electric shovels work on the mountain. FMI had to build an electric substation at the base of the mountain to supply the shovel's 7,200-volt electrical needs. The first shovel at the Chino pit (pictured above) took a 9-man crew, this electric shovel  (shown below) takes one man and a truck driver. 

The P&H seen on the shovel stands for the name of the two partners who originally formed the company that built the shovel, Pawling and Harnischfeger. They were located in Milwaukee, Wisconsin, and furnished heavy machinery and drilling equipment world wide. The company since has been purchased by Komatsu of Japan. So if you see trucks around Silver with Komatsu across the door you will know what they're up to.

After blasting a precise area, these gigantic shovels can fill the huge ore trucks in three scoops. Workers blast and shovel their way across the mountain top, each swath taking about 50 feet off the height of the mountain. These massive trucks haul about 480,000 pounds of ore each load and there are about 10-15 trucks running to and from the mountain at any one time. They take their loads to one of four places. The waste debris and dirt from around the outside of the mountain is taken next door to the old Continental dump site where they pile this material onto the stockpile which dates from 1910. Waste rock is taken to the cover material stockpile at the Continental site.  Note the staircase mounted to the front of the truck. These trucks are weighed and tracked electronically so the company knows exactly what and how much is being mined at any one moment.

There are two different types of ore being mined at Hanover mountain—Oxide and Sulfide ore. Sulfide ore is hauled to the crusher at Chino mine. There it's crushed and sent down a quarter mile long conveyor to the Ivanhoe concentrator (also called the mill). After being crushed into a powder, the ore is processed using the flotation method which produces a concentrate (copper mud) that is dried and sent to Miami, AZ or El Paso, TX for further refinement.

Oxide ore cannot be processed with the flotation method but can be leeched. This ore is trucked out to the leach field east of the Kneeling Nun there to be leeched with sulphiric acid and water. After percolating down through the ore and rock, where it picks up minute particles of copper, the leeched solution winds up in the bottom of the pit looking like blue or purple water. This solution is pumped to the SXEW plant in rubber pipes where it is processed into 200 pound copper plates. These plates are also sent to Miami and El Paso by truck.

To date they have taken about 425 feet off the mountain's height and the plan for the future is to keep digging until the ore runs out. This won't happen for another 10-15 years when the mountain becomes a pit extending several hundred feet into the earth.

It was a thrill and a privilege for us to see this work in progress, work that is the lifeblood of our area. We present this story in the newspaper tradition of reporting on local mining operations, a tradition that dates from some of the first newspapers published in Grant County.

Christopher Saxman
Cub reporter
Hanover Beat,
With assistance from Terry Humble