We continuously explore for construction aggregate, which we primarily find in sand and gravel deposits in areas north and south of Memphis. Aggregate must meet strict performance standards and it can only be found where nature put it. Currently we operate one CME 550X drill rig (watch video of drill rig in action) to explore for these deposits. The equipment and techniques we use cause minimal impact to the property and it is often difficult to tell where we have drilled. Drilling consists of advancing eight inch diameter augers in five foot intervals. The material is drilled to the surface where it is evaluated for a variety of characteristics such as quality and rock content. A small amount may be collected for laboratory analysis and the rest is put back into the hole. The hole is completely filled in before we leave the site.
Each hole is logged and surveyed. Following the field work, the company’s geologist will review the results and attempt to reconstruct the depositional environment that existed when the material was put there long ago. If material with the right characteristics is identified, then we will estimate the resource to determine how much material could be mined. Of course mining and exploration are quite different and many factors will determine if a resource can be mined economically. This process does not cost the property owner anything and will not obligate them in anyway, but could lead to a profitable venture for both parties.
We cannot do anything until we are “permitted” to do so by the local, state, and federal government. Environmental management and safety are key components of the planning process. It is in our own best interest to fully plan our operations because of the very high costs associated with mining. Property owners who we lease land from demand that we know how the land will be put back following the mining activity. Besides, we want a safe and environmentally sound work place just as much as anyone. Memphis Stone & Gravel Co. is regulated by numerous agencies that make certain we operate in a responsible manner including the Tennessee Department of Environment and Conservation, Mississippi Department of Environmental Quality, US Environmental Protection Agency, Mine Safety and Health Administration, and US Army Corps of Engineers.
We must first strip the overburden away from the resource. The type of equipment used in stripping depends on the digging conditions and could include scrapers, tractors with pans, and excavators and haul trucks. Once the overburden is out of the way, we mine the resource using hydraulic excavators or draglines. We manage the mining by laying off small pits approximately, 5 acres, and proceed in a “checker board” pattern, moving the overburden directly to a previously mined out pit. We are careful to separate the fertile topsoil from the other parts of the overburden during stripping operations.
We feed the raw material on conveyor systems using wheel loaders. All the material we mine is unconsolidated and is relatively easy to dig using standard construction equipment. This means we do not have to “blast” the material free, rather just dig it out. The material is also naturally moist and does not generate dust when it is mined or transported. From the pit, the mined material rides on an over-the-land conveyor belt system to a wash plant for processing. We have some conveyors stretched out almost three miles. There are a lot of advantages to using conveyors, including lower operating cost and reduced truck traffic. In some cases the raw material has to be trucked to the plant.
Some of the mined material (e.g., clay gravel) can be sent directly from the mine to the job. But most of the material that Memphis Stone & Gravel Co. produces is “washed” sand and gravel. We use water at approximately 8,000 to 10,000 gallons per minute to process the aggregate. Put simply, we separate the sand from the rock and wash out the fine (clay) particles. The sand and rock are placed in piles to drain the water away from the material. All the water we use in the process is recycled! The water we use and all the water that comes into contact with our operations (i.e., rain) is managed to minimize impacts to the environment. The “washed” material is then used to make products such as ready-mix concrete, asphalt concrete, landscape materials, and drainage rock.
Reclamation is one of the most important steps in the mining cycle! State law requires us to put back all the soil that we must remove to get the resource, but it just makes good sense to do it. Good reclamation can add value to the land by creating beautiful lakes and land that is very conducive to development. We have often made land owners proclaim that “the land looks better now than before” following our reclamation. Everything we have mined in Shelby County, except where we are actively mining, has been developed. Reclamation involves backfilling the excavated areas with the overburden or tailings from the mined material. Again, we separate the fertile topsoil from the bulk of the backfill. Our immediate goal is site stabilization through revegetation using a mixed variety of grasses best suited for that purpose.We will often return the land in pasture suitable for livestock or plant trees to create a new forest.
Reclamation is now, more than ever, an important driver for our mine planning. We work with property owners to develop a solid reclamation plan that will keep in mind future development goals. Ultimately our goal is a property owner who not only enjoys the income provided by mining the resource, but is happy with the land when we are finished.
Take a virtual tour through the "Mining Cycle". This presentation includes lots of photos of key parts of our mining operations, including many from our award winning reclamation projects. This informative presentation also illustrates the type of mining equipment used around the world.
Check out some articles written about our operations:
"Deposit Exploration - Sum of All Parts" describes how MS&G is an industry leader in finding high quality aggregate deposits and treats land owners as partners right from the start.
"Toning it Down" describes how we manage noise at the mine with emphasis on broadband backup alarm technology.
"Water Wisdom" explores how the industry is lowering water cosumption at the mine and finding new ways to improve recycling of its process water.
"Like a Good Neighbor" highlights MS&G's Good Neighbor Trucking Policy.