Expansion is driven by growing speculation, new exploitation technologies as well as some new markets. The main motors behind the gold industry are a handful of multinationals who heavily promote jewelry consumption. Indeed concentration of power in this industry is staggering. In the last five years the concentration has become more extreme 'with a rush of acquisitions and ill-tempered spats' according to the Financial Times. Demand for gold remains strong so long as middle-classes convert their affluence into the wearing of jewelry, a phenomenon the gold industry is banking on continuing.
China is also a substantial and growing market.
All mining has historically caused major environmental problems. One of the biggest problems is the fact that metals like gold are found in sulphide ores which when exposed to air become acidic. This in turn becomes sulphuric acid when brought into contact with water, a common enough ocurrence in areas with underground water supplies, dissolving toxic heavy metals like arsenic, copper and iron. Old mines, in particular, where shafts were sunk deep into the water table without any thought of future problems, often end up contaminating groundwater permanently. Levels of copper as low as two parts of per million are considered lethal to humans while concentrations as low as five parts per billion can inhibit fish reproduction, which means that the fish population might dwindle over a period of years.