BHP Billiton, Tintaya Mine, Peru

Tailings Dam Engineering and Construction
BHP Billiton Tintaya S.A., Peru

MWH provided the design and support for the construction and commissioning of a new, 58- million ton tailings facility for the BHP Billiton Tintaya mine in southern Peru. The project consisted of a 46-meter-high centerline, cycloned tailings dam, a 3,500 horsepower (HP) tailings slurry pump station, approximately 20km of tailings and reclaim water steel pipeline, a versatile tailings distribution system, a tailings cyclone station, a reclaim water barge and booster pump station, approximately 12km of power transmission line, access roads, and a SCADA system for remote operation of the facility. MWH also provided a detailed tailings operation and management plan for the designed facility. MWH completed the designs and studies for all phases of this project as detailed below.

Scoping level studies and designs: MWH performed studies to evaluate alternative methods of expanding the existing tailings facility, and to determine alternative methods and locations for disposing tailings. We analyzed capital and operational costs, potential environmental and socio-economic impacts, and suitability to existing mine operations. We then ranked the alternatives accordingly. BHP Billiton selected a new tailings disposal site (Huinipampa) based on the results of the studies. MWH completed conceptual designs for this facility that included a centerline cycloned tailings dam, tailings pump station, tailings cyclone station, tailings distribution systems, reclaim water pump system, and support facilities (access roads, power transmission lines and data communications systems).

Pre-feasibility studies and basic engineering designs: MWH performed basic engineering designs and completed the pre-feasibility studies for the new Huinipampa tailings facility. Pre-feasibility level costs were estimated for direct capital, owner’s costs, sustaining capital, operational costs, and closure costs.

Feasibility studies and detailed engineering designs: MWH completed feasibility studies and detailed designs for the facility. Based on these documents, BHP Billiton’s executive management approved a capital budget for $20.8 million (US) for the project, consistent with the cost estimate that MWH presented in the feasibility level studies.

Detailed engineering and engineering support: MWH managed a diverse engineering work force consisting of local Peruvian engineers and technicians, Chilean engineers, US-based engineers, and engineers from BHP Billiton Tintaya mine. Engineering for this project included a wide variety of disciplines; among the most important were geotechnical, mechanical, hydraulic, piping, civil, electrical and environmental.

Construction quality assurance: MWH performed the construction quality assurance (CQA) for the project. The construction team consisted of a diverse workforce including engineers and technicians from Peru, USA, Brazil, and Chile. Construction of the project was completed in 12 months.

Environmental Impact Assessment MWH managed the baseline permitting studies for this new tailings facility and completed the environmental impact assessment (EIA). The EIA was approved by the Ministry of Energy and Mines of Peru.