Ask Bob Dylan
The Answer My Friend is Blowing in the Wind
Stockpile width will be a function (cotangent) of the height which is governed by local conditions. If there is likely to be windblow near population or reserves then you might have to enclose the piles in buildings which conform to the local bylaws.
A pleasant pile height is slightly less than 15m and calls for tracks of about 35m.
Some manufacturers supply machines with 60m track; I am presently lumbered with 3 of these monstrosities; 
but sensibly they should be limited to the acceptable 14-15m stockpile height. ■
Stock Pile Width for Blending Reclaimer
I am going to be involved for system design of a 6.5 MT Iron Ore Benification Plant along with 3.5 MT pellet plant.For 6.5 MT Iron Ore Benification Plant , daily requirement of Iron ore fines approx 20000T. After unloading thrugh BOXN & BOBR wagon it have planed for storage at least 15 days with 4 different stickpile ( In two different row,two stockpile)with 80000t capacity in each stockpile.Now my question is how i have decided the stock pile width,it is corelated with the Blender reclaimer boom length & material repose angle.Where most of cases i have seen with 30 or 32 m stock pile width. So share me about the some idea for the fundamental & limitation of stock pile wdth ■