An external environmental audit of PT Freeport Indonesia (PTFI) mining operations and support facilities was conducted in November 2008. The audit, coordinated by Montgomery Watson Harza (MWH) was conducted by five independent auditors comprised of environmental professionals from various countries, including Indonesia. “MWH was selected after undergoing a transparent and highly competitive tender. This audit is one of the realizations of PTFI’s commitment, as listed in the 1997 Environmental Impact Analysis 300K document,” explained PTFI Manager – Environmental Andi Mukhsia. Its tailings management is a feature of the second in IM’s major series on the operation, in the September issue.
This external audit is conducted voluntarily every three years, with the aim of measuring and evaluating company performance in the area of environmental management, adherence to the laws and regulations of the Indonesian government, and fulfillment of PTFI’s commitment to complying with environmental best practices as part of the international mining community. This last audit is the fifth external environmental audit at PTFI since 1996.
The final audit report was published in July 2009 after receiving constructive input from related operational departments and PTFI Environmental Department. The executive summary of the complete audit report is available at http://www.fcx.com/envir/pdf/audits/Executive_Summary_2008.PDF. PTFI’s response to the recommendations as of July 2009 may be viewed at http://www.fcx.com/envir/pdf/audits/Findings_Matrix_Responses_July_2009.pdf. This response will be updated periodically through routine communication with operational departments in order to gather the latest data, project status, and other supporting data that supports implementation of auditor recommendations.
Generally Freeport gets a glowing report. Its tailings management is discussed in the September issue of International Mining, as part of a series of articles on this great mine thast will extend into 2010. MWH says current Freeport management practice of controlled riverine tailings transport and deposition to an engineered area remains the best option available for the operation. The lateral limits of environmental impacts associated with tailings disposal within the Modified Ajkwa Deposition Area (ModADA) are fixed and defined by the levee systems.
Impacts associated with the fraction of tailings, not reporting to the ModADA, remain consistent with those anticipated and covered by the Government of Indonesia (GOI) approved 300K ANDAL. Freeport commissioned a detailed evaluation of sediment retention technologies, and large-scale implementation and evaluation of these techniques is ongoing.
Freeport hydrology staff has continued to refine the groundwater regime, including flow gradients and velocities for the ModADA and adjacent areas including Timika, using monitoring data from wells and piesometers. MWH recommends that the groundwater flow and transport model for the ModADA be finalised, including potentimetric levels and local and regional groundwater gradients.
The current procedures and high level of commitment of all relevant Freeport departments has greatly facilitated the effective implementation of the tailings ARD control program. Overall, the results suggest that the risk of ARD from tailings depositing in the bulk of ModADA in 2008 has been low to negligible. An independent review of the ARD program by Environmental Geochemistry International (EGI) provided an interpretation of recent ModADA geochemistry data and found that the Acid Neutralising Capacity (ANC) to Maximum Potential Acidity (MPA) ratio continues to meet or exceed the Standard Operating Procedure (SOP) target of 1.5 at all locations. Further recommendations for prevention of ARD in the ModADA are provided in the Audit report.
MWH continues to recommend that Freeport evaluate the environmental implications of the Otomona River post-closure. Each option poses challenges that should be carefully evaluated in relation to regulatory requirements, so that preferred options may be incorporated into current planning activities.
Freeport has completed a comprehensive Tailings River and Management Plan (TRMP) Incident Action Plan (TIAP) written in both English and Bahasa Indonesia. The TIAP is a significant improvement in emergency planning, but certain aspects need refinement.