Some Aspects of Fixation of Exploratory Parameters Including Optimum Drilling Grid in the Context of Multivariables of Secondary Enriched Iron Ore Deposits

Majority of the Iron ore deposits of the world in general and India in particular have originated due to the secondary enrichment of Banded Iron Formations. It is estimated that Indian as high grade iron ores to the tune of 9 6 billion tonnes. The geostatistical method of calculation of optimum drilling and, is presented, in the context of multivariables and examples are presented for three iron ore deposits. Based on studies on a number secondary enriched hematite iron ore deposits, with respect to many variables, in different iron ore belts in India, an optimum drilling grid of 50-60 m is suggested. Taking an average insitu bulk density of 3 3 tonnes/m³, the quantum of drilling works out to be 120-85 in per million tonnes of iron ore.

The quantum of drilling, indicates the necessary but not the sufficient condition. An example of specifications of the ore from buyers and improvement of quality in the mineral dressing plant are presented. For deciding the grid at local level, the data of blast holes which are drilled at a closer interval, can be used. It is stressed that always geology has to be taken into account, and if necessary a few inclined holes ate to be drilled. A few adits are also suggested for the sake of completeness of exploration. It is suggested that the approach should be comprehensive rather than viewing the problem in parts.