The capacity analysis is identical to that for an elongated pile except that the arc length of the center section is substituted for the value L in Equal 4 above. A kidney-shaped pile such as that formed by a radial stacker is merely a variation of the elongated pile. The total capacity of an elongated pile is the sum of the results of Equation 1 and Equation 4. Where: r = radius of end half cone in feet Where: R = radius of end half cone in metersįor a value of A of 38 degrees, Equation 4 reduces to:ħ.81 x 10 -4 R²LD = capacity in metric tons…………………………….(5)Įquation 5 expressed in English units is:ģ.91 x 10 -4 r²ld = capacity in short tons………………………………….(6) The capacity of the center section of the elongated pile is given by: The end half cones can be combined to form a single conical pile which can be analyzed using Equation 1, 2 or 3 above.

The capacity of the stockpile can easily be determined by considering the pile as two separate volumes. The elongated stockpile and its variations are the most common stockpile form in high capacity installations. For example, if 1600 kg/m³ (100 lb/ ft³) material is being stockpiled on soil with an allowable bearing pressure of 14 680 kg/m³ (3000 lb/ft³) the maximum permissible conical stockpile is about 27.4m (90 ft.) high and has a total storage capacity of about 56 000 metric tons (62 000 short tons). More importantly, because the conical pile occupies such a small ground area in relation to its volume, soil pressures on large piles can exceed the bearing strength of the local soil. This results in very long conveyors and supports and accompanying large foundations to withstand the loads on the conveyor. One disadvantage is that very high stockpiles are required to attain large storage capacities.

The main advantage of the conical pile is that it can easily be built by dozing equipment or a fixed belt conveyor.

Substituting this value for A reduces Equation 1 to:Ĩ.18 x 10 -4 R☽ = capacity in metric tons………………….(2)Ĥ.09 x 10 -4 r³d = capacity in short tons…………………(3)įor convenience, typical stockpile capacities have been tabulated in both metric and English units in Table 1. This fact will become important later in considerations of live storage capacity.įor many common materials, the angle of repose, A, is about 38 degrees. One should also observe at this point that one-half of the capacity of the stockpile is in the lower 1/5 of the pile. Increasing the height of the stockpile by 26% results in a doubling of the stockpile capacity. This means that the capacity of the conical pile grows very rapidly as the height (and hence the radius of the pile) increases. Note that the capacity of the conical stockpile varies with the cube of the radius of the pile. The total stockpile capacity is given by:ģ.14 (Tan A)R³ D/3000 = capacity in metric tons…………………(1)Ī = angle of repose for material to be stockpiled The conical stockpile is the simplest and easiest to analyze. Stockpiles fall into two general categories: conical and elongated. Calculating Stockpile Capacity: Once the minimum storage capacities which will assure maximum mill output are known, the appropriate stockpile configuration must be determined.

Define stockpile