Laserfiche WebLink
SCHEDULE TO NOTICE OF VIOLATION <br />Notice of Violation No.: CV-2020-001 <br />NATURE OF VIOLATION: <br />Failure to conduct subsidence survey; failure to protect hydrologic balance <br />ACT, REGULATION, OR PERMIT PROVISION(S) VIOLATED: <br />ACT SECTION(S): III(1)(m) <br />121(2)(a)(I) <br />REGULATIONSECTION(S): 2.05.6(3) <br />4.05.1(4)(c) <br />2.05.6(6) <br />4.20 <br />PERMIT SECTION(S): 2.05.6(6) <br />Exhibit 55B <br />Exhibit 60E <br />PORTION OF THE OPERATION TO WHICH THIS NOTICE APPLIES: <br />The operator, Mountain Coal Company (MCC), had previously notified the Division of subsidence that had <br />occurred during the afternoon of Monday October 13th, as a result of development mining under South Prong <br />Creek. During the inspection it was apparent that the depth of cover at the location where the subsidence had <br />occurred was extremely shallow, on the order of 30' (thirty feet). <br />The inspection prompted further research of materials relating to subsidence in the approved Permit <br />Application Packet (PAP). The requirements of Rule 2.05.6(6) - Mitigation of the Impacts of Mining <br />Operations; Subsidence Survey, Subsidence Monitoring, and Subsidence Control Plan - are addressed by <br />sections 2.05.6(6) of the PAP text and Exhibit 60E - Subsidence Evaluation for the Southern Panels, Apache <br />Rocks West, & Sunset Trail Mining Areas. <br />Exhibit 55B - Stream Channel Parameters and Changes due to Mining -Induced Subsidence - is a separate study <br />that analyses the potential subsidence impacts to stream basins overlying the mine workings, based on the <br />subsidence evaluation made in Exhibit 60E. On page 13 of Exhibit 55B the authors conclude that "The mining - <br />induced subsidence impacts on existing stream channel parameters and basin sediment yield are not significant. <br />Any changes in channel characteristics will occur gradually and reach the new regime over a period of several <br />years" <br />The subsidence predictions in Exhibit 60E are made by subject matter experts based on a range of observations <br />and assumptions concerning the mining that will be conducted. The authors assume that the typical overburden <br />depth will range from 400' to 2,100', with a minimum depth of 375' (see pages 15, 20, 36, 39). In their summary <br />of anticipated effects the authors state that "at least several hundred feet of rock will typically exist between any <br />mine -induced surface fractures and the upper part of any mine -induced fractures above the caved zone in the <br />mining panels. Therefore, from a practical standpoint, no interconnection between the surface fractures and the <br />mine workings is anticipated. Again, under a worst -case scenario, if a surface fracture were to occur <br />concurrently within an area controlled by faults or bedrock lineaments, there could be interconnection between <br />adjacent sandstones. However, even under these conditions, the fractures would not extend through the <br />Page 3 of 4 <br />