Ok Some good questions, every pit is different, sometimes the...

Ok

Some good questions, every pit is different, sometimes the ramp as we call it might follow the pit wall all the way around in a continuous spiral, it all depends on the structure of the ore body, he way it dips, quite often the ramp will switch back under itself from one corner to the other of the pit and could then switch back again, again to keep the access on one side of the pit to allow mining on the other, mining engineer's go over this with a fine tooth comb and at the end come up with a pit design which is very easy to follow, more often than not with a huge pit of 300 meters in depth will be done with a series of cut back's, the reason for this is to make the smallest possible entry point at the surface to get down and access the ore body ASAP, you wouldnt start diging the full pit design width stripping million's of tonnes of waste and not accessing the ore, most big operations like Mount Keith Nickel will have a series of cut backs, possibly up to 10 cut backs and the pit is done in stages to always ensure that the ore body is accessed to allow ore for the mill.

The ramps are generally the same width all the way down, however in alot of cases the ramp will be reduced to a one lane ramp with a turn around area of the point of reduction, when things get down to one lane it wont be to far before the bottom as this creates huge congestion, you would typically find this on smaller mine design's, mines like Mt Keith wouldnt mess around with one lane ramps as these types of projects are massive, ramps do need to be accounted for when deciding the width at the top. Mining company's will always look for the most economical way to mine making those walls as steep as possible to avoid overburden removal

Watching a massive wall failure is really something to be seen, its like an avolanch.

Cheers