During the period 1841-1851, the Mount Lofty Ranges region was the locus of Australia's first mining era. This was the decade prior to the discovery of gold in the eastern States, when virtually all of the metalliferous mines in Australia were located in South Australia, where the population grew, as a result, from 15,000 in 1841 to 64,000 in 1851. The 1840s mining boom followed the discovery of silver-lead ore at Glen Osmond, which is located in the foothills of the Mount Lofty Ranges on the outskirts of Adelaide. The Glen Osmond discovery was quickly followed by the discovery elsewhere in the ranges and mining exploitation of a large number of mineral deposits, the most significant being the copper deposits at Kapunda (1844) and Burra (1845). These valuable industrial developments came at a crucial time in the history of South Australia; in the early 1840s the newly created colony was on the verge of bankruptcy, and was saved from collapse by the mining boom. The mining of copper ores at Kapunda and Burra caused the first major social and economic decentralisation away from Adelaide, and by 1850, Burra with a population of 5000 was the largest inland town in Australia and seventh largest overall. In 1850, minerals constituted 67% of the value of exports from the colony, and wool 29%. A large proportion of the population was directly or indirectly dependent on mining, and South Australia was the third largest copper producer in the world. These mineral deposits, the first being exploited less than five years after the colony was established, had a profound effect on settlement. They brought about a major influx of capital and immigrants into South Australia after the depression of the early 1840s, and provided employment for a large number of people. Land was surveyed for mineral tenements, mining townships and agricultural purposes. Basic road networks were created during this period to enable ore to be carted to Port Adelaide for shipment to Wales, and also to allow heavy machinery to be delivered to the mines.