DELINEATION OF ORE OCCURRENCES IN ORE RESERVES APPRAISAL WITH MICROMINE PACKAGE

Abstract

The ore quality requirements include: cutoff grade, minimum thickness of ore body, maximum permissible thickness of interbeds  of barren rocks or offgrade ore within the ore body perimeter,  minimum metropercent (metrogram) calculated as the product of  cutoff grade and minimum ore body thickness. Recently, mineral  reserves appraisal has put in practice automation within specialized programs of geological–surveying data processing. The  principal subject in automation of ore occurrence delineation in  Micromine package and the topic of this article is delimitation of an  ore body across its thickness using the data from the ore quality  requirements. This becomes necessary when geological data on  external boundaries are absent, which is typical of variable  morphology ore bodies: mineralized dikes and zones, ore folds,  skarns, ore chimneys, etc. Previously, before this study, Micromine  package implemented appraisal of composite material reserves in  the following scenarios: along boreholes, by benches, by intervals,  by geology, by content. The programmers implemented ,since  version 16,the ore occurrence algorithm based on the ore quality  requirements using a method in a separate menu tab: Drillhole/  Compositing/ Grade (GKZ).The main kinds (parameters) of the ore occurrence algorithm are the Strictly rules and the Relaxed  rules.. The article describes general framework of the analysis of  ordinary ore occurrences, and similarity and distinctions in  performance of the main kinds of the algorithm. Technically, the ore  reserves appraisal based on the ore quality requirements should use  the algorithm where all the requirements are maximum possible  taken into account. In Micromine package, such algorithm is the  Strictly Rules with the option “Do not allow contiguous composites”.  Practically, there arises multivariate coupling and delimitation of ore  bodies in the identified ore occurrences. The article gives a few  somewhat formalized examples to illustrate appropriateness of one  or the other method of ore occurrence delineation. Automation of ore reserves appraisal results in essential acceleration of data processing. The described algorithms enable calculation and  statistical processing of numerous alternatives of ore occurrences  based on the input variables of the ore quality requirements: Cб, Mп,  Mр, MC within a short time provided that the data are prepared and clean.