Questions and Answers of Geological Engineering

Consider a narrow vein overhand stope using cut and fill, as shown in the sketch. Cemented, hydraulic sand fill of modulus Ef is placed in the stope as mining proceeds up dip in a rock mass of
Laboratory test data from 4-in. (10.2 cm) diameter samples, 4 in. (10.2 cm) long (not cemented) are given in Table 7.5. Estimate the hydraulic conductivity of the fill(in./h).
A hydraulic sand fill is tested using a falling head per-mea-meter that has a tube diameter of 1.27 cm (0.50 in.), sample diameter of 10.2 cm (4.0 in.), sample length of 20.4 cm (8.0 in.), and a
Old room and pillar workings extend under Hometown where the strata roll to the horizontal (depth = 1,750 ft, 533 m) and where additional protection in the form of river-run sand fill is placed
A large mechanized cut-and-fill stope in hard rock is cable bolted on a square pattern as shown in the sketch. A single 5/8 in. (1.59 cm) diameter cable bolt is installed per hole; cables have an
Consider the cable bolting array shown in the sketch. Develop an expression based on a requirement for equilibrium in the direction normal to the vein dip that brings into association vein dip ?,
Consider a vein of medium width (50 ft, 15.2 m) that dips 65? and is mined by vertical crater retreat (VCR), as shown in the sketch for the previous problem. Level interval is 150 ft (45.7 m). Layout
Consider a medium width vein (50 ft, 15.2 m) dipping 65? and mined by overhand mechanized cut and fill (MCF) with a level interval of 200 ft (61 m) as shown in the sketch. (a) Derive a bolting
With reference to the sketch, verify the cable bolting formula below. If the formula is unsatisfactory, then derive a substitute formula based on a dead weight load analysis. Here S = spacing (ft, m)
Consider a vertical shrinkage stope W (ft, m) wide, H (ft, m) high filled with muck having a specific weight γ along a strike length of L (ft, m). Further suppose wall friction angle φ' and angle
Derive a formula for the chimney cave height H shown in the sketch. Note that the initial void is roughly circular in plan and has a radius of a (ft, m). The circular region is h (ft, m) high. An
If the excavation width a in Problem 8.2 is 105 ft (32 m), the initial height of the circular region is 14 ft (4.3 m); the arch extends 35 ft (10.7 m) above the floor. What bulking porosity is
Consider the stope in the inclined vein shown in the sketch. If the stope height measured along the dip is 115 ft (35.1 m), the true width of the vein is 35 ft (10.7 m), and the bulking porosity, as
A panel block caving system operates at a depth of 4,250 ft (1,417 m) as shown in the sketch. Dimensions of the panels are 150 ft by 300 ft (45.7 ?? 91.4 m) in plan. The initial undercut is 21 ft
With reference to Problem 8.5, the caved ground has a specific weight of 105 pcf (16.6kN/m3); the angle of friction between muck and rock is 23◦, while the angle of internal friction of the muck is
A panel block caving system operates at a depth of 1,295 m. Dimensions of the panels are 46 m by 92 m ft in plan. The undercut is 6.4 m high. Initial bulking porosity at the start of the cave, which
A panel block caving system operates at a depth of 4,250 ft. Dimensions of the panels are 150 ft by 300 ft in plan. The undercut is 21 ft high. Initial bulking porosity at the start of the cave,
Block caving studies indicate the rock mass has an associated bulking porosity of 0.015. A caving panel is developed 1,570 ft (479 m) below ground surface. Suppose the panel is A square feet in plan
A circular ore pass 13 ft (4 m) in diameter has a muck cushion that extends 9 ft (9 m) above the bottom of the ore pass. The ore pass is vertical and extends 150 ft from level to level. The muck has
A proposal for panel caving a massive ore zone using undercuts 250 ft by 600 ft (76.2 × 183 m) in plan and 14 ft (5.4 m) high is made. If the bulking porosity is 0.075 and caving occurs directly
With reference to the paper by F. Kendorski (chapter 4, 1977) and the example calculations for Mine C (which relates to Mine B), a wall shear check is made using the equation FD = Ff + Fr + Fri. The
With reference to Problems 8.5 and 8.6, 9 ft wide by 12 ft high grizzly drifts below the undercut level are first supported with 3/4 in diameter, grade 55 resin bolts 6 ft long (grouted full length)
With reference to Problems 8.5 and 8.6, 2.7 m wide by 3.7 m high grizzly drifts below the undercut level are first supported with 3/4 in diameter, grade 55 (379 MPa yield strength) resin bolts 1.8 m
A semicircular arched back heading 14 ft (4.3 m) wide and 17 ft (5.2 m) high is driven due north. Two joints are present; both strike due north. Set 1 dips 60◦ east; Set 2 dips 60◦ west. No other
A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 12,750 psi, and φ = 29◦. Specific weight of
A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 88 MPa, and φ = 29◦. Specific weight of rock is
With reference to the data below, an open pit mine has reached an economic limit (3,000 ft, 914 m depth), so underground mining is being considered using a block caving method. A mainline ramp 16 ft
A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 12,750 psi, and φ = 29◦. Specific weight of
A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 87.9 MPa, and φ = 29◦. Specific weight of rock
A long wall panel 6,200 ft long with a face length of 820 ft is planned for a seam 1,300 ft deep and 16.5 ft thick. Mining is full seam height. Assume UK conditions apply. Find:1 The maximum
A long wall panel 1,900mlong with a face length of 250mis planned for a seam 396m deep and 5.0 m thick. Mining is full seam height. Assume UK conditions apply. Find (in m when):1 The maximum
A long wall panel 6,200 ft long with a face length of 820 ft is planned for a seam 1,300 ft deep and 16.5 ft thick. Mining is full seam height. Assume UK conditions apply. Find:1 The maximum
Consider a single long wall panel in a seam mined full height of5mat a depth of 400 m. The panel has a face width of 300 m; panel length will eventually reach 3,000 m. The seam is flat. Mining occurs
Coal is mined 15 ft high underground in flat strata by the long wall method at a depth of 1,500 ft. Panels are 750 ft wide and 7,500 ft long. Assume US conditions, then considering trough subsidence,
A solution mine for nacholite that is processed into soda ash is developed by wells 1,800 ft below the surface in the Piceance basin of Colorado. The mine will produce about 1 million short tons per

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