Minerals Refining Company

Commercial Applications

Proven. Safe. Ready.

Minerals Refining Company’s separation technology is offered commercially in the form of a modular plant installed near or adjacent to an existing coal preparation facility. Built to chemical process safety standards, the HHS plant intercepts a facility’s waste stream prior to the thickening process. Once the coal has been recovered, cleaned and dewatered, the high quality product is suitable for blending or briquetting.

An Industry Challenge

To meet quality specifications, run-of-mine coal is typically sent to preparation plants to remove unwanted impurities and de-water the clean coal. Over time, the mining industry has introduced technologies to improve separation and increase recovery of coal. However, cleaning and dewatering ultrafine coal is the least efficient and costliest step in processing coal.

At the ultrafine level (-325 mesh) the circuitry is costly, cleaning performance is poor, and moisture removal has been difficult to impossible. As a result, billions of tons of ultrafine coal have been mined, only to be thrown away in impoundments because of a lack of efficient, cost-effective separation and drying technologies.

The MRC Answer

Mineral Refining Company’s innovative separation technology uses a hydrophobic (“water-repelling”) liquid to displace water and hydrophillic mineral impurities from the surface of fine and ultrafine coal particles, converting waste slurry into a quality, salable product, and in the process reducing the amount of waste sent to impoundments.

Testing of MRC’s HHS Process on a wide variety of coal waste streams has consistently yielded a product well within range of usual quality specifications: ash contents typically ranging from 3% to 6% and moisture values of 4% to 8%. The carbon recoveries are in excess of 80% to 90% – and all of it from material that would otherwise have been discarded.

Location and Type of Coal Feed Ash % Product Moisture % Product Ash % Reject Ash % Combustible Recovery % Sample
Eastern Kentucky Mine A – PCI/Thermal 67.5 6.8 3.8 88.3 72.9 Deslime Cyclone OF
Southern WV Mine B – HV Met 53.0 6.8 3.4 84.4 79.7 Deslime Cyclone OF
Western Pennsylvania Mine C- Thermal Pitt 8 40.4 3.9 4.3 85.8 89.4 Screen Bowl Effluent
Southern WV Mine D – HV Met 53.6 3.5 3.9 88.0 84.7 Deslime Cyclone OF
Northern WV Mine E – HV Met 13.7 4.9 5.0 76.3 96.7 Screen Bowl Effluent
SW Virginia Mine F – LV Met 7.0 3.8 2.1 64.8 97.1 Screen Bowl Effluent
Southern WV Mine G – LV Met 10.7 3.8 3.1 79.4 97.7 Screen Bowl Effluent


The HHS Process offers a low-cost, highly profitable method of extracting greater value from your existing product stream. Our plants and operational agreements are tailor-made to each processing facility to ensure cost-effectiveness and a new revenue stream for our customers, with minimal capital.


Despite the small fraction of fine and ultrafine coal in a processing facility’s product stream, recovering this additional product could have a remarkable effect on the economics of a preparation plant. In addition, due to the quality specifications of product from the HHS Process, it may be possible to raise the gravity in the other processing plant circuits and improve recovery of the coarser coals.


The potentially recoverable coal in fine slurry typically represents 35% to 65% of the solids being pumped from the thickener to the waste impoundment. Recovering this coal as a saleable product will extend the life of the slurry pond and reduce the potential for a black water spill.



Customers pay premium prices for coal with coking characteristics, used to produce iron and steel. Coal sold for coke production requires higher purity levels (3% to 6% ash) compared to steam coal (7% to 12% ash). Advanced dewatering processes, such as plate-and-frame filter presses, have been used to dry high-value ultrafine coal in this market, although high equipment cost and limited moisture removal have severely restricted industrial applications. The HHS Process offers an economic solution to recovering this high-value product.


Increasingly stringent environmental regulations, large increases in the availability of conventional and shale gas for power generation, and higher domestic mining costs have created a more difficult and declining market in the U.S. for steam coal. Because the value of thermal coal is based on its energy content, low ash and moisture contents are critical.


Safety is the highest priority for MRC. Consistent with the safety measures taken in the design and construction of MRC’s Pilot Plant, all commercial HHS plants will be equipped with numerous safety features. Most notably, the entire HHS Process is performed under a nitrogen-inerting atmosphere.