History of PGM mining

Platinum group metals ("PGMs") are rare precious metals, which frequently occur together in nature as constituents of various ores and minerals. PGMs are a family of six metals: platinum, palladium, rhodium, iridium, ruthenium, and osmium, all of which have similar chemical and physical properties and are grouped together in the periodic table.

PGMs are regarded as strategic industrial metals because of their extensive use in the petrochemical, automotive and electronic industries. In many applications, it is impossible to substitute PGMs economically and technically.

Historical Development of PGMs

Discovery of PGMs

Platinum-containing artefacts have been dated as far as 700BC. However, the earliest references to platinum are to grey, dense pebbles associated with alluvial gold deposits in the sixteenth century. These pebbles could not be melted alone but would alloy with and contaminate the gold to the extent that the gold bars would become brittle and impossible to refine. The pebbles became known as platina del Pinto, named after granules of silvery material from the Pinto River, a tributary of the San Juan River in the Chocó region of Colombia.

Malleable platinum was first produced in 1789 by the French physicist P.F. Chabaneau and was fabricated into a chalice, which was presented to Pope Pius VI. The discovery of palladium was claimed in 1802 by the English chemist William Wollaston, who named it after the asteroid Pallas. Wollaston subsequently claimed the discovery of another element present in platinum ore; this he called rhodium, after the rose colour of its salts.

The subsequent discoveries of iridium (named after Iris, goddess of the rainbow, because of the muticoloured nature of its salts) and osmium (from the Greek word for "odour," because of the chlorine-like odour of its oxide form) were claimed by the English chemist Smithson Tenant in 1803. Ruthenium, the last PGM to be isolated and identified, was given a name based on the Latinised word for Russia by its discoverer, the Russian chemist Karl Karlovich Klaus in 1844.

Unlike gold and silver, which can be readily isolated in a comparatively pure state by simple fire refining, the PGMs require complex aqueous chemical processing for their isolation and identification. Because these techniques were not available until the turn of the 19th century, the identification and isolation of PGMs lagged significantly behind that of silver and gold.

Development of applications for PGMs

The steady growth of the platinum industry has been evident since 1950. The oil boom in the 1950s, and the consequent development of the petroleum refining industry where platinum is used as a catalyst, provided the first major impetus to platinum's market development.

Growth in platinum demand was further stimulated during the 1960s by a hugely successful diamond jewellery campaign initiated by De Beers in Japan. Government restrictions on private ownership of gold created a window of opportunity for platinum to expand its share of the Japanese jewellery market.

Platinum's growth momentum was maintained by the introduction in 1968 of the US Federal Clean Air Act, the genesis of worldwide legislation to restrict noxious tailpipe emissions from vehicles. The subsequent development of platinum-based autocatalysts to meet legislated emissions limits created a major new market segment for platinum.

Japan's booming economy of the 1980s and early 1990s propelled the platinum jewellery market to new record levels with 13 years of successive growth. In addition to these dominant influences, new industrial applications, particularly in electronics, with the growing use of platinum in hard disks, and in the manufacture of high-purity glass used in lap-top computer screens, and the successful introduction of small platinum investment products (such as proof and bullion coins) have steadily increased platinum demand to a record 5.2 million ounces in 1997. Furthermore, over the past few years China has emerged as a rapidly developing consumer of platinum, most of its offtake being used in jewellery applications and the balance in industrial uses.