Minerals Research and Recovery plant rising from old slag pile
COTTONWOOD -- A slag recovery project that has been in the planning and approval stages for six years can see light at the end of the tunnel.
The 100-year-old towering pile of copper mining slag that dominates the center of Cottonwood, at the back of the Verde Valley Fairgrounds, is to be recycled as aggregate and blasting material. The removal project will finally get underway by year's end.
Tom Hurkett is the Project Manager for Minerals Research and Recovery that originated by harvesting slag from Ajo, Ariz.
The company first built an 8,000-square-foot steel warehouse to for storage of the product and a small shop.
The operation will use service trucks like the ones used by CTI to transport cement products from the plant in Clarkdale. Then a steel structure was built to support 16 steel silos. Conveyors will feed the silos from the crushing equipment that will be built in the center of the slag pile. The top of the silos will be 45 feet tall, but the conveyors from the crushing equipment will rise to 65 feet. Hurkett says the equipment will be no taller than the slag now stands.
The first of the massive silos was delivered last week. This structure was contracted to Horizon Steel in Tucson, which does a lot of work in the mining industry.
A typical front-end loader moves the material through a crasher with filters for grading. Then the product moves up a conveyor to load the 18 wheel trucks.
Hurkett says crews moved about 100,000 tons of slag just to create a space to build the plant.
"My biggest worry with the whole project was making the cut -since we didn't have any controls-- in the slag here to make way for the facility which required excavation and moving and we didn't have one complaint."
He said that the biggest noise is in the construction of the plant.
Hurkett says MRR makes about eight different products, or different grades of the glassy stone. They don't do bonded abrasives such as sand paper, but the products are used for roofing material and sand and water based blasting.
Tom says the company is hoping to be finished with construction and start up around December.
He said there would be no concern about dust. "Dust is very controlled, it is a salable product for us."
In addition to the standard front end loaders, the operation uses specialty equipment for the processing site.
"It is very difficult material to process. It is very abrasive and destroys everything it touches, so we have various handling techniques, to carrying and process."
The company began harvesting slag in Ajo in 1985; about 30 years ago. As the slag began to diminish at the Ajo site, MRR looked around to find a new source of material.
"We have looked at most of the slag piles in the West, but there are very few that meet our requirements. We were down in Douglas originally and looked at that slag, but that was a "tolling" smelter and there were concentrates from a number of different mines. They brought in waste and trash and recycled material."
"The chemistry was all over the board and not predictable. The reason we were in Ajo and the reason we are here, is this slag came from one single ore body and one source, one concentrate from a single mine. And it doesn't change."
"We sell a lot of material in California which is very strict on the environmental reviews so we have to be careful."
How long will the Cottonwood United Verde Extension pile last?
"Slag piles grow; there are no records. We did aerial surveys and made estimates on what is there. We thought there was 3 million tons in Ajo, but there was probably 4 million tons. Everyone always wants to know how long you will be here. We will be here till it's gone."
The initial estimate is 20 years.
The operation will provide good jobs for workers.
Hurkett says the "guys we have hired so far have been really good."
He says the company program has a good retirement, health and dental plan.