The interaction of acidophilic iron and sulfur-oxidizing bacteria (A. ferrooxidans, L. ferrooxidans and A. thiooxidans) with a bornite-chalcocite ore specimen from the Salobo mine, Carajás, Brazil was examined at pH 4 and pH 2 to determine the effect of secondary mineral coatings on bioleaching / copper solubilization. In order to select for bacteria that could attach to mineral surfaces and promote colony formation (bacterial growth), polished sample chips were suspended in the bacterial consortium for 24 hr, and then transferred to fresh media for growth, providing a limited window for colonization. After 4 weeks growth, and using scanning electron microscopy, the bornite-chalcocite ore possessed colonies on all bornite-chalcocite surfaces, evenly scattered individual cells on the non-sulfidic minerals in the ore specimen, and secondary copper phosphate on the bornite-chalcocite ore at pH 4 versus iron phosphate in the pH 2 reaction systems. Viable cell counts in both systems were two orders of magnitude higher than the original inoculum by the end of the experiment indicating that bacteria are released from mineralized biofilms when growing on bornite-chalcocite surfaces. At pH 4, the lack of iron in solution and in the precipitates formed on the bornite-chalcocite ore sample, along with an examination of the mineral surface after removal of the copper phosphate precipitate with ion cleaning indicates a preferential leaching of chalcocite, with no significant solubilization of bornite. While secondary mineral formation, i.e., copper-phosphate formed at pH 4, can limit the recovery of copper, iron phosphate mineral coatings formed at pH 2 did not impact bacterial growth or copper recovery.