As well as limestone, other raw materials are required to manufacture cement clinker.  These are commonly  clay or shale, sand and iron oxide.  Not all these are required in all cases, but their availability needs to be known to determine what qualities of cement can be made from the limestone deposit.  In many plants these materials can be made available from the by-products from other industries, such as fly ash from power stations to replace partly or wholly the clay component or waste materials from the steel industry including slags and oxide rich sludges.

Approach

My expertise is in the materials involved in making cement and concrete and the process which achieves this.  The advantage of looking at raw materials in this light at a very early stage is that an assessment of the likelihood of a successful project can be made before expenditure of considerable sums on detailed geological and engineering examinations.

Initially it is necessary to determine the quality of the deposit in terms of chemistry, consistency, geometry, accessibility and influence on the water table.  If there is no available information then a geological survey including a set of broadly spaced boreholes will be necessary.  However, for a deposit to have been considered seriously as a source of cement raw material there will generally have been some previous exploration and it is necessary to access all possible data concerning the potential resource

In this preliminary desk study, in conjunction with publically available or commercial geological data any available borehole data are assessed for:

• Chemistry, found from the analysis of cores recovered from drilling the deposit.

• Consistency, also found from the core analyses as well as a study of available geological data from national surveys, commercial explorations etc.

• Determination of the deposit geometry.  Are the available boreholes sufficiently close to interpret the shape of the deposit underground?  (For example is the deposit undulating, or dipping or thinning in any direction?) or are further drillings necessary to discover this?

• Accessiblity, including the depth of overburden, if any, the presence of geological faults, the nature of the ground in terms of the ease of building quarry roads or whether transport by conveyor may be necessary etc.

                1.      The local authorities in most parts of the world will require a five year (or longer) plan of                 how the deposit is to be worked for environmental reasons.

                2.      The quarry manager needs to have a plan of how to operate the quarry in order to                         provide the optimum quality of product to the cement plant over the life of the quarry.                     This is vital in order to prevent exploitation of the easier parts of the quarry in the short                 term then leading to serious problems for the later part of the life of the quarry.

The quarry plans are best managed by means of computer software which collects data both from the initial drilling programme and from the ongoing exploitation of the quarry as further data is made available from exposure of quarry faces and dusts made available from drilling for explosive charges.  This software is widely available commercially, but requires geological expertise to establish and maintain.

A Harrisson 2011