Laserfiche WebLink
• Previous Subsidence Experience <br />Coal mining to the North Thompson Creek Mines was first initiated in <br />1952. Between 1952 and 1966, full extraction room and pillar mining was <br />utilized 1n both No. 1 Mine and No. 3 Mine under overburden cover vary- <br />1ng from approximately 150 ft. to over 600 ft. The locations of these <br />mined-out areas are shown on Maps A and B for No. 1 Mine and No. 3 Mine, <br />respectively. <br />Several methods were utilized to investigate previous subsidence experi- <br />ence. Aerial photographs of the mine area, flown at a scale of approxi- <br />mately 1:28,000, were analyzed for possible subsidence effects. Tra- <br />verses across the surface above the mined-out areas were walked by an <br />• engineer experienced in surface subsidence phenomena. Individuals 1n- <br />volved with operations and engineering at the mine site during the pre- <br />vlous mining activity from 1952 through 1966 were questioned regarding <br />subsidence phenomena. <br />The results of the surveys and discussions indicated no known surface <br />subsidence phenomena resulted from the full extraction roan and pillar <br />mining. No visible manifestations of subsidence Here observed on the <br />aerial photographs or during the surface traverses: The conversations <br />with mine personnel did not indicate any known surface subsidence <br />effects. <br />n <br />U <br />12 <br />