A technical discussion of mining operations in the lime and cement industries of Zambia and Malawi
This document constitutes a brief discussion of the total concept of mining limestone, particularly for lime and cement manufacture. Actual case studies in which the writer has participated have been used to demonstrate the methods used by the various operators and their attitude to matters such as the environment has been described. The document has been written to be presented as suitable material for the Degree of Doctor of Philosophy, however, on reading several cotemporary theses which deal solely with the matter concerning the degree, the writer has chosen to produce a document that compiles material from a multitude of sources, including the writers own experience which he thinks may be of interest to mining students. The part of this document that complies with the requirement to "advance science" is in the use of explosives and the principles of rock breakage, this is the main area of the writers expertise and is to be found, in Chapters ten and eleven. The method of blasting and the reasoning for its evident success, challenges some, and agrees with other, mathematical theorem that have been presented previously. Most mathematical theorem use either perfect models, or require so many variables that the accuracy of the maths becomes doubtful, because of this, their usefulness to the mining engineer is limited. Chapter eleven explains how explosives work in surface mining and identifies enhanced effects. The writer believes that these enhanced effects are the result of coincidences in the pulses of the shock waves. The writer first noticed the effects of a shock wave on rock when designing huge blasts for strip mining of coal in Zambia, where the rock had to be totally shattered but remain in place, further experiments in the Falkland Islands with spacing and timing, finally led to application in African limestone quarries. The blasting described at Chilanga has been designed to first shatter the rock then produce further breakage in the enhanced heaving process, in addition, the imperfect rock formation provides a perfect example of using explosives to blend the various grades of material. Many photographs are included of the results of blasting and as the practice is still current, the readers are able to visit Zambia to examine the effects for themselves.