The conventional methods used for delineation of Manganese orebodies and prediction of quality consists of analysing surface geology and then sub-surface exploration by drilling. However, these methods are time-consuming and expensive. We are seeking solutions that will enable us to predict orebody delineation, its grade and physical conditions like lumps/fines accurately.
The Manganese orebody in our mines is lensoidal, discontinuous, fragmented in nature and generally occurs up to a depth of 60-70 m from surface. The conventional methods used for delineation of Manganese orebodies and prediction of quality consists of analysing surface geology and then sub-surface exploration by drilling. As per the mining guidelines, for General Exploration, drilling at an interval of 100x100m is required to delineate irregular, discontinuous orebodies. For detailed exploration, close-spaced drilling at an interval of 50x50m is necessary to delineate the Manganese ore bodies. Both methods are time-consuming and are very costly; however, these methods are statutory.
In addition to determining ore body delineation, we also need to:
a) predict lumps/fines ratio and the quantity of low/medium/high grade ore and
b) determine the hardness of orebodies for determination of lump/fines ratio during blasting of orebodies
At present, during exploration, predictions on orebody delineation are made based on the analysis of the drill cores or the drill cuttings. Drill cores are crushed and screened to assess the lumps/fine ratio. Besides, the prediction can be inaccurate if the variation is high within the small pockety nature of orebody.
In addition to drilling, geophysical methods such as magnetic, electrical resistivity, electromagnetic, gravity and seismic methods are commonly used in understanding the orientation of the orebody. Ground-penetrating radar (GPR) is another electromagnetic method used for very near-surface applications. Due to the similarity in properties of the ore body (Manganese) and host rock (Shale, Laterite), the efficacy of geophysical methods is not adequate to meet the objective. Therefore, the final delineation of the orebody and the prediction of its quality can be ascertained only through exploration based on drilling and analysis of the drill core/cutting samples. The geophysical methods can help us reduce the exploration cost by providing data in advance about the occurrence of the orebody pockets. However, geophysical methods alone, are not deterministic, therefore, can only provide an indicative assessment.
We are seeking solutions that will enable us to predict orebody delineation, its grade and physical conditions like lumps/fines accurately, without using any of the conventional techniques mentioned above.