Coal Age

MAR 2018

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March 2018 www.coalage.com 37 dust compliance continued mize exposure while still maintain- ing a safe line of vision in relation to nearby activities, including operation of the shuttle car. • When coal is being carried by the conveyor up the tail boom of the miner to be loaded into shuttle cars, with dust also being carried along with the coal being loaded (although water sprays are useful in this situa- tion, they do not stifle all of the respi- rable dust liberated into the air). • When tramming the continuous min- ing machine (CMM), which causes the operators or helpers to experience increased spikes in respirable dust ex- posure when picking up and moving cables and hoses in dry roadways. Overall, CMOs reported that their per- sonal body positioning was the most im- portant action they could take to reduce their exposure. Common corrective ac- tions discussed across the mines included: • Advancing the ventilation curtain toward the face for exhaust face ven- tilation (keeping the CMO outby the end of the curtain) or standing be- hind the curtain (when safe in terms of visibility) when using blowing face ventilation. • Stepping further back from the face or turning their body away from the miner while cutting. • Moving to the discharge of the cur- tain on a blowing ventilation section to situate themselves by intake air. • Proceeding with certain work prac- tices — specifically, lowering the cut- ting boom — at a much slower pace to minimize stirring up excessive dust. • Completing housekeeping practices that reduce personal or work crew ex- posure, which can be done during oth- erwise idle time. An example is while waiting for the next shuttle car, a CM operator can use a wash-down hose to clean material away from water spray manifolds on top of the miner. Although these actions could be and were taken in both regular and low-coal, the low-seam miners noted that they faced a greater challenge. CMOs noted that they consistently positioned their bodies and chose work practices to minimize expo- sure even while not wearing the CPDM, but these actions were less likely to be sus- tained in low-coal, due to the added envi- ronmental restrictions. Importantly, CMOs indicated that us- ing the CPDM and referring to their dust data cards have changed their personal habits. One CMO stated, "You think more where you should be to minimize expo- sure. It's kind of on your mind more." Sources of Dust and Corrective Actions for Roof Bolters Prior to the regulation, the CMO was typ- ically the occupation targeted in terms of reducing exposure to respirable coal dust. Alternatively, roof bolters did not always receive as much emphasis. As one dust technician said, "The roof bolter is at a bigger risk for black lung than the CMO. The problem is that the CMOs, they got black lung hammered into them and the dangers of it. They're more aware. We've left the roof bolters behind, haven't paid the attention to their health that's been needed." Several of the participating mines not- ed additional proactivity and motivation on behalf of their roof bolters in response to the CPDM data. Common times when increased exposures were reported by this group included: • During initial drilling, particular- ly during the first four inches until the drill bit is completely contained within the drilled hole. After the ini- tial drilling, bolters indicated that the drill steel can become clogged and a dust plume spurts out of the hole. • Drilling while downwind of the CMM due to additional dust being gener- ated and liberated into the air by the CMM. In many cases, these decision time points can be enhanced through mining sequence planning and pro- duction mapping. • While changing dust collector bags and during practices associated with this task, such as proper bag sealing and storage. Consistent corrective actions shared to mitigate exposures caused by the above situations included: • Drilling the initial few inches much slower, despite the common habit of drilling fast. • Increasing the distance between the CMM and the bolter if the bolter is going to be downwind of the CMM, which allows for greater mixing and dilution of generated dust. • Keeping the roof bolter upwind of the continuous miner. • Keeping the roof bolter out of the re- turn air when not bolting. • Alternating changing of the dust col- lection bags so that one person is not getting all of this specific unavoid- able dust exposure. Additional Sources and Corrective Actions In addition to the CMO and roof bolter, researchers found that additional ODOs wear the CPDM whether it is for compli- ance or for informational purposes on site. This helped to identify additional job tasks impacted by the CPDM data. Rock Dusting Although rock dusting can impact the CPDM dust data, rock dusting must be completed to protect mines from coal dust explosions. Several mines indicate rock dusting more between the shifts to avoid exposing miners during their working shift. Additionally, the sites dis- cussed how different seasons impact rock dusting practices. In the summer, the increased humidity helps moisten CMOs indicated that using the CPDM and referring to their dust cards have changed their personal habits. One CMO stated, "You think more where you should be to minimize exposure. It's kind of on your mind more."

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