Cyanide leaching of gold ores is the most commonly used technology for the extraction of gold. In response to the severe impacts of uncontrolled release of cyanide or cyanide-containing waste into the environment, a technical working group constituted by the European Commission has defined BAT, i.e. “best available technologies”. In order to achieve international comparability, a manual on best practice of cyanide management commissioned by the Australian Federal Department of the Environment and Heritage was also consulted for this Master Thesis. The Bolivian goldmine Kori Kollo, run by Empresa Inti Raymi S.A., has been confronted with strong criticism regarding severe environmental pollution due to neglecting safety measures. In order to balance these accusations, which largely lack of scientific basis, with an independent scientific analysis, the environmental performance of the goldmine was investigated and documented. Drawing on the locally acquired data, a comparison of the status quo with the guidelines of BAT was conducted. The following points of criticism are paramount: The first phase of the project, the mining of oxidized ores, initially lacked of the liner for the leaching pad. Moreover, the integrity of the legally required monitoring reports is questionable for the following reasons: the omission of measured values, its inconsistency with externally commissioned measurements and the lack of response to elevated values. Regarding the second phase of the project, the mining of sulphide ores, no record of contamination by waste-rock exists, but the safety measures documented did not meet the BAT standards. In addition, monitoring of emissions to air only included two parameters (TSP and PM-10), neglecting the crucial parameters of particle shape and chemical composition of dust. In summary, the gaps and inconsistency of the monitoring reports make it difficult to assess the environmental performance of the Kori Kollo goldmine. However, the overall planning procedure seems to have been conducted with a technological standard approximating that of BAT.