Between 1830 and 1850 Chilean silver mining grew at an unprecedented pace which transformed mining into one of the country's principal sources of wealth. The rush caused rapid demographic, infrastructural, and economic expansion in the semi-arid Norte Chico mountains where the silver deposits lay. A number of Chileans made large fortunes in the rush and made investments in other areas of the economy of Chile. By the 1850s the rush was in decline and lucrative silver mining definitely ended in the 1870s. At the same time mining activity in Chile reoriented to saltpetre operations.