H.Amdt.919 - Amendment provides the mining industry with more time to install a new generation of fire-resistant conveyor belts; provides funds for MSHA to purchase a new generation of dust monitoring devices to limit black lung disease, and ensure that breathable air requirements of the MINER Act of 2006 are properly implemented; requires that the Secretary of Labor conduct a study on substance abuse by miners with recommendations for policy changes in consultation with all interested parties and requires the Secretary to report the findings within six months of the bill's enactment. If she deems it feasible and effective, the Secretary shall be authorized to establish a miner substance abuse testing, rehabilitation, and treatment program within MSHA in consultation with the interested parties.