Gold in the year 2000: A global overview

Abstract

Following the dramatic increase in the gold price during the late 1970s, the western world's gold production increased rapidly from about 750 t to more than 1200 t in 1985 and to the current level of 1900 t in 1993 and 1994. A slight drop in gold production during 1994 and a shortfall of demand over supply of 199 t are in agreement with a detailed evaluation that suggests a growing undersupply of gold to the market-place over the next five years. Volatility of the gold price during 1994 was low and currently investors do not regard the metal as the important hedge against risk that it was in previous years. Nevertheless the fundamentals are sound and a progressive increase in the gold price is predicted. Cash costs per ounce of gold mined are commonly $210–280 and total costs are generally $50–80 higher. Increased costs, legislative constraints and threats of royalties are encouraging many companies to consider alternative exploration plays, particularly in South America, Eastern Europe and the former Soviet Union, and West and East Africa. In addition to South America, considerable successes in terms of new discoveries and joint ventures have been reported from West Africa and the former Soviet Union respectively. The Indian subcontinent also has considerable potential for new discoveries. Successful exploration requires integration of geophysical surveys, especially aeromagnetic-supported mapping and high-resolution magnetic surveys, and regolith geochemistry surveys based on a thorough understanding of the development history of the regolith and of the consequent, sometimes multistage, dispersion of the gold. Identification of target areas and specific targets can be achieved by modelling of fluid flow and fracture connectivity through one or more of seismic profiling, fractal analysis of veins and shear zones, and stress mapping. On a more detailed scale it is important to recognise the many controls of gold precipitation including sulfidation, phase separation, the contrasting roles of thio- and chloro-complexing in different fo2-pH environments, and adsorption on semiconducting sulfide surfaces. Important recent technological advances within the industry include the development of a diamond wire rope to aid stoping of the conglomeratic ‘reef’ horizons and the growing use of bacteria-catalysed sulfide oxidation ('bio-leach') to process refractory gold ores. © 1996 Taylor & Francis Group, LLC.