Physics behind it
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freebody_diagram_2.jpgMost hoisting systems have a vertical orintation. This means there are two forces acting in this system the downward force is done by gravity.











freebody_diagram_3.JPGWhen a hoisting system does not have a vertical orientation, but instead it is on some sort of an incline, there are many other forces acting on it. The force acting downward is gravity, but the orientation that this system travels is inclined at some angle theta. The effective pulling downward is mg*sin(theta).



F1 = mgsin(theta)                                    
F2 = mgcos(theta)                                    
F3 = mg                                                     
F4 = mgcos(theta)*µ                                
T = -mg                                                    
N = -mgcos(theta)                                   



Standard Equations (Used in Mining)

RPS = [(x+y+z)sin(theta)] + [(y+z)cos(theta)(0.025)] + [(x)cos(theta)(0.1)]
                  gravity                          conveyance friction                      rope friction

RPS = maximum rope pull
x = weight of rope
y = weight of conveyance (lbs.)
z = weight of load (lbs.)
theta = angle of incline

SL = [(D/V) + 0.4V + 12]/(3600/TPH)

SL = Tonnage of ore in each skip
D = Depth (ft.)
V = Velociy (ft/sec)
TPH = Tonnage per hour

SF = 7 - (0.001)L