thank you, page-11

i forgot to calculate ramps and possible switch back's, 20 - 25 meter width for Cat 789B 200 tonne trucks, not a big deal when cosidering the 100 meters i left for the pit foor, a huge pit floor would usually be designed for the mine to go underground through a port hole and have work space at the bottom and allow plenty of saftey, rock falls, ETC. Open cut then under ground is a very common practice to access very deep ore body's as open cut mining becomes less eficient at a certain depth, sometimes operation's run both at the same time.