Laserfiche WebLink
• <br />0 <br />• <br />2.05.4(2)(e) <br />(2)(g) Sealing or Managing Mine Openings Exploration Holes Other Boreholes or Wells <br />The mine portals will be sealed in accordance with Map 28, Portal Entry Seals <br />and Map 30 Portal Entry Water Tight Seals. Vent shafts will be sealed in <br />accordance with Map 29 Shaft Seals. The exploration and monitoring holes <br />will be sealed in accordance with the requirements of Rule 4.07. <br />(2)(g) Drill holes, not completed to aquifers will be sealed by replacing cuttings or other <br />suitable media in the hole and placing a suitable plug 10 feet below the ground to <br />support a cement plug or other media approved by the Division to within 3 feet of the <br />ground surface. <br />PR -12 <br />/9 <br />?PRO IV <br />1111411.0 <br />Drill holes completed in non artisan aquifers will be sealed using cement or <br />other suitable sealant by placing the sealant to extend 20 feet above and <br />below the water bearing zone. A surface plug will then be placed in <br />accordance with the above paragraph. The hole will be marked. <br />Two types of seals will be considered for installation at the Bowie #2 Mine <br />upon mine abandonment. If mine water in -flows are experienced in the mine, <br />a water -tight seal will need to be installed to plug the portals and contain <br />potentially degrading mine water from flowing from the abandoned portals. <br />The design of the concrete water -tight seal was taken from Bureau of Mines <br />Information authored by Cheken, Garrett, and Pitt. They developed an <br />equation used for design after work done in Africa on seals which where able <br />to withstand hydrostatic pressure in excess of 6,000 psi. The equation is as <br />follows; <br />L = (p *a *b) /((a +b) *fc) <br />where; <br />L = Length of plug, ft. <br />a = width of entry, ft. <br />b = Height of entry, ft. <br />p = Hydrostatic pressure, psi. <br />fc= Allowable compressive strength of rock or concrete, whichever is the <br />lesser, psi. <br />The height and width, a and b, of the portal entries is 8 -feet and 20 -feet, <br />respectfully. The roof, ribs and floor will be cleaned to competent material but <br />will not be recessed into solid rock or coal. The maximum calculated <br />hydrostatic pressure, p, for the seal will be 60 -feet of water__or.26 psi <br />(measured from the seal elevation to the piezometric surface of the upper <br />perched water bearing zone). Coal will have the lowest compressive strength, <br />2.05-80 02/10 <br />