In an attempt to recover all available coal, the Waterloo Coal Company in Jackson, Ohio, purchased a Mud Cat auger dredge from the Mud Cat Division of Mud Cat International to reclaim previously discarded coal particles 3/16 inch diameter and less.
For 18 years, equipment in the Waterloo Coal mine’s preparation plant could not wash and dry these small particles. Pieces of coal that small were discarded to slurry ponds along with the excess water from the preparation process.
Then the company built a new preparation plant, installing new equipment to process the small coal particles. “That’s when we decided it would be to our advantage to start reclaiming the small pieces that had been discarded over the years,” said Phil Bowman, vice president.
Waterloo Coal has used the same slurry pond since 1955. The pond, which remains in service while the Mud Cat is at work, covers about five acres and contains an estimated 40,000 tons of usable coal. According to Bowman, the coal deposits are at least 20 feet deep.
The Mud Cat brings to the job its unique capability of floating in a mere 27 inches of water. After the water evaporates from the coal particles, the coal settles into solid layers. Water must be pumped in over the coal for the Mud Cat to float. The fact that Mud Cat can float in only 27 inches of water was as important consideration for Bowman when deciding on the dredge.
Waterloo Coal Company’s Mud Cat can reach depths of 10 feet below the surface of the water, and by lowering the water level, it can reach all 20 feet of coal in the slurry pond. (Different models dig deeper.)
The Mud Cat-10’s 8-ft wide underwater auger is attached to a hydraulic boom at the front end of the machine. As the auger rotates, it chews up the coal deposits, forcing the material into an intake tube. Material is pumped about 140 feet to the new preparation plant, where the water, mud and fine particles are separated by putting the slurry through a Vor Siv and a Townly Cyclone and then a model 200 Vor Siv Classifier. After air drying in CMI dryers, the coal is sold to users in southeastern Ohio.
“The same water will be recycled several times, first pumped into the preparation plant by the Mud Cat, then flushed out with the wastes from the coal, then pumped back in again by the Mud Cat,” said Bowman. “That way we don’t continually need new water.” The Mud Cat operation was initially obtaining 10-15 tons of coal per day. After modifications to the system were made, the amount of usable coal reclaimed doubled.
“There was really no other simple way to reclaim those small particles of coal,” said Bowman.
Mud Cat’s Mud Cat Division now offers a variety of dredge models to meet the special requirements of each coal recovery application.
Mud Cat Div. of Mud Cat International