Original paper

Optimale Methodenkombination in der Exploration

[Optimal Combination of Exploration Methods]

Wellmer, Friedrich-Wilhelm; Greinwald, Siegfried

Kurzfassung

Ein Explorationsprogramm sollte so konzipiert sein, daß es möglichst kostengünstig und schnell bohrwürdige Ziele liefert, die die besten Chancen für eine Lagerstättenentdeckung bieten. Dies erfordert, jeweils angepaßt an das Explorationsenvironment, eine optimale Kombination von geologischen, geophysikalischen und/oder geochemischen Methoden, um in einer Explorationsfläche die linearen oder kleinflächigen Bohrziele zu entdecken. Je kleiner und je höffiger die Flächen sind, desto detaillierter und kostenaufwendiger können die angewandten Verfahren sein. 3 Explorationskategorien werden unterschieden:

Abstract

An exploration programme should be planned in such a way that it produces drill targets having the best chance for a discovery of an ore deposit in a time and cost efficient way. This requires adapted to the special exploration situation an optimal combination of geological, geophysical and/or geochemical methods, to find in an exploration area drill targets, which are either linear or relatively small areawise. The applied exploration methods can be the more detailed and costly the smaller and the more favorable the exploration areas are. 3 exploration categories are distinguished: a) large area exploration with an example of the search for volcanogenic Cu-Zn-deposits in the Archean rocks of the Canadian Shield (airborne and ground electromagnetic and magnetic methods, basal till sampling). b) small area exploration with two examples: search for volcanogenic Cu-Pb-Zn-deposits in Mesozoic volcanics (soil geochemistry, puls electromagnetic method) and for stratiform Pb-Zndeposits in Paleozoic clastic sediments (electromagnetic and magnetic methods, gravity) in the Northamerican Cordillera. c) exploration around a newly discovered volcanogenic Cu-Pb-Zn-occurrence in Mesozoic volcanics of the Southamerican Cordillera (geology, geochemistry, mise-a-la-masse, induced polarisation). Costs of the exploration methods and the time necessary for a typical exploration programme are given. It is demonstrated that the specific costs per anomaly area increase exponentially by advancing to the final drilling stage.

Keywords

Case studiesmethods (methods combination)explorationairborne methodelectromagnetic methodmagnetic methodgeochemical prospectiongravity methodmise-a-la-masseinduced polarizationinfluencedeposit typerocksmetalscoststime