Surface mine (1)
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The document outlines a step-by-step procedure for determining the minimum required operating room for parallel cuts, based on various specifications of a truck and shovel. Critical calculations include safety berm width, truck centerline distance, working bench dimensions, cut width, and bench slope. The final results inform the drilling and blasting pattern for optimal operation.
Surface mine (1)
- 1. GhulamMehdi (23101) Q# Find the minimum required operating room for parallel cuts. The required values are given below; Bench height=40 ft. The minimum clearance b/w the outer truck tire & safety berm=5 ft. Bench face angle=70◦ Truck capacity=85 tons Truck Width=16 ft. Tire rolling radius=4 ft. Working bench=102 ft. Cut width=60 ft. Swell factor=0.90 Holes Diameter=12 (1/4) inches Shovel Specifications: Shovel capacity=9 yd3 Dumping radius at maximum height (B) =45.5 ft Maximum dumping height (A) =28 ft. Radius of floor radius (G) =32.25 ft. Maximum cutting radius of the shovel (E) =54.5 ft Maximum cutting height of the shovel (D) =43.5 ft Illustrate by using 8-Steps to solve this problem. Ans# Step 1: We required the safety berm. For this we know that the tire rolling radius is equal to 4 ft. Assumed to the angle of repose 45◦, the width of the safety berm will be 8 ft. Step 2: The centerline of the truck to the crest distance is find in such a way that the clearance distance b/w the safety berm and the wheel of the truck is 5 ft plus the safety berm width (8 ft) and half of the truck width (16/2=8 ft). Truck centerline to the crest distance (Tc) =21 ft Step 3: Shovel specifications are essential to considered. Shovel Specifications: Shovel capacity=9 yd3 Dumping radius at maximum height (B) =45.5 ft
- 2. GhulamMehdi (23101) Maximum dumping height (A) =28 ft. Radius of floor radius (G) =32.25 ft. Maximum cutting radius of the shovel (E) =54.5 ft Maximum cutting height of the shovel (D) =43.5 ft Step 4: The shovel dimensions are given above. With the help of these dimensions and the truck centerline to the crest distance (Tc), we find the desired working bench. WB= Tc + B +G WB = 21 + 45.5 +35.5 WB =102 ft Step 5: Now find the cut width. For this purpose we know that; Wc=(Swell factor) 2*G Wc= (0.90) 2*35.25 Wc= 63.5 ft In design cut width we should be kept the cut width less than this value. Hence 60 ft has been assumed. Step 6: Now find the Safety bench. We know that; WB = SB +Wc Putting values, we have; SB =102-60 SB =42 ft Step 7: The slope of the bench can find by this formula: Slope = Tan-1 (Bench Height)/(E-G) Putting values; We have; Slope = Tan-1 (40)/(54.50-35.25) Slope = 64.3◦ Thus the shovel can easily scale the 70◦ bench face. Step 8: For drilling and blasting pattern, Using a common thumb rule, the burden (B) is given by; B =25(De/12) B =25(12(1/4)/12) B =25 ft The spacing is equal to the burden.
- 3. GhulamMehdi (23101) S =25 ft.