Question

7. (30 pts) An open cut uranium mine is excavated in the shape of an inverted frustrum of a right circular cone (ignoring the berms). See the figure below. The volume of this shape is equal to 2 The slope of the pit is 1 (45°). At ground level the radius of the cut is 120 m. At a depth of 15 m, a vein of uranium ore starts. The average ore density is 3.2 g/cm3. Excavation of the uranium ore to a depth of 50 m from the surface yields 100,000 t of uranium. What is the total amount of ore excavated in cubic meters? What is the ore grade? Is this grade of ore realistic? Is it economically feasible to mine this ore at present uranium prices?

Answer 1

Given +R,R,) Sol 50 tants 17Om 2o m 3S ann 5om 11 Ca K120m mass Uranium Cm toforres (O G S devg ty CP) 3.2 -- Volume 3,13x (0 3200 m3 Volume of di3ged out minera 2 V : 3.4 +C120) +55x12 x 3 5 OIS S3 Uaniumlume of Grade Uranium Avai lalrle Volume 300 oIS. Peacen t Y.s availalle Oran Le fueen avaane grade , NOw Our Uranium Undes e aveae i's Comes gade Real'slic . s grade yes Yes Peas: ble ranum PrCe Present Hthis al mine