Mining at Berta would be carried out by open pit methods.
The drilling and blasting should be evaluated together, as drill hole diameter and explosive charge factors that ensure correct fragmentation, must be reconciled. Geotechnical and rock mechanics data is used to make a correct estimation of equipment and cost.
According the geotechnical information of the deposit, two material types, mineral material and waste have been defined.
Two drilling diameters, 51/2" and 6 1/2", based on bench height and the geotechnical characteristics of similar deposits were assumed.
It has been assumed that the base load will be HEAVY ANFO (HANFO), and for loading a column, ANFO NORMAL. Any holes making water will be loaded with an emulsion of 60% HEAVY ANFO.
The loading and hauling should be analysed together to determine the compatibility of the units. The aspects to evaluate are:
- Physical Match: the dimension of the equipment must be compatible. The height of the dump trucks must be such that the loading equipment is capable of that height to load them.
- Productivity Match: the number of passes required to load a truck must be taken in account. High productivity is considered a match of 3 to 4 passes. It is planned to use 25ton dump trucks and 3.7yd3 loaders which results in medium productivity, as they require 5 passes to load a truck.
As for drilling and blasting, the GRAVEL type material has an important eff ........
