Mining Contract: Maintenance Free Filters for Continuous Miner Scrubber Systems

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Contract # 75D30119C06228
Start Date 9/1/2019
End Date 8/31/2021
Research Concept

Continuous miners generally have flooded-bed dust scrubbers installed on them as a dust remedial tool. These scrubbers were invented in the late 1970s and their design has changed little since that time. This research will offer a redesigned, maintenance-free scrubber filter for the continuous miner that could be paired with more efficient, effective design elements on a scrubber.

Contract Status & Impact

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Continuous mining machines are used as the primary production equipment in mechanized room and pillar coal mining operations. Continuous miners are also used in longwall mines to develop access to longwall panels.

The coal extraction process generates respirable and float coal dust which is detrimental to the safety of miners if not removed via mine ventilation systems. Coal dust can exacerbate ignitions of methane and carbon monoxide explosive fuel mixture formations underground, generating large explosions. The shock fronts produced by the detonation event can damage mine infrastructure and seriously or fatally injure any underground mine workers.

Prolonged overexposure to respirable coal mine dust can result in serious health conditions such as coal workers' pneumoconiosis (black lung) or silicosis. Silicosis developers when miners breathe respirable coal mine dust with elevated levels of silica. A wide variety of different techniques have been developed to reduce dust exposure underground. Adequate ventilation removes dust thereby lowering the exposure to miners.

Strategically installed water sprays on the continuous miner suppress dust at generation sources preventing particles from being airborne. The water sprays are also powerful at moving air and directing dust particles away from the miners. Flooded-bed dust scrubbers are installed on many continuous miners to capture the dust-laden air from the active face. The scrubbers are active dust scrubbing systems powered by vane axial fans. A series of inlet ducts on the installed scrubber pull in dust-laden air and redirect it through a water-flooded mesh screen filter.

The screen is the primary filter element and captures dust from the airstream on its water-flooded surface. The screen is usually made of 20 to 30 layers of individual mesh filters which filter the dusty air. The cleaning efficiency and pressure drop across the screen increases with the number of filter layers. The air then flows through a demister downstream of the filter to capture any water droplets escaping from the screen.

Research by NIOSH has shown that these scrubbers have the ability to reduce dust concentrations close to the face by about 60-90% under optimal operating conditions. However, continual deposition of dust on the screen surface clogs it, causing low airflow through the scrubber which can increase dust exposure of miners underground. The continuous miner is then required to be brought under supported roof for screen maintenance. This lowers the availability of the machine for coal production which, in turn, lowers the operational efficiency of mining operations. The screens in their present form have been in use since the 1980s, and new research focused on the development of maintenance-free filters that could exhibit a similar cleaning efficiency to those like the current filters is needed.

This University of Kentucky will design and develop efficient, non-clogging, self-cleaning, drop-down replacement filters of the existing fibrous type screens used currently in the flooded-bed dust scrubbers on continuous miners.

Page last reviewed: April 19, 2022
Page last updated: January 30, 2020