This chapter explores two distinct efforts to develop mining from the end of the eighteenth century and through the nineteenth century. Prior to the onset of industrialization, miners concentrated on the search for gold and precious stones. Nevertheless, provisioning plantations and mines with expensive and scarce iron tools was one of the enduring bottlenecks of the colonial period. Iron ore, forged into implements and machinery, was essential to support the perceived sources of Brazilian wealth: gold, precious stones and sugar. In the twenty-five years prior to independence, the Portuguese Crown attempted to implement Brazil's first industrial policy in order to advance iron mining and forging. This proto-import-substituting-industrialization policy aimed to produce domestically the tools and machinery needed for precious mineral mining and sugar production.

With the return of the Portuguese Crown to Lisbon in 1821, this strategy was abandoned in favour of creating attractive conditions for foreign miners to invest their capital and technology in the search for precious minerals. In response, the St John d'el Rey Mining Company formed in London for the purpose of mining for gold in Minas Gerais. The company's charter dates to 1830, and its mine in Sabará opened in 1834. The unique experience and archival records of this company provide a valuable window into the conflicts and constraints that private enterprise faced in Brazilian mining.