Ausenco was retained by Compania Minera Antamina S.A. (CMA) to perform a full range of engineering services on their copper/zinc concentrate slurry pipeline system – the first multi-product slurry pipeline system in a mountainous region.
Our work on the pipeline system began with a comprehensive feasibility study and continued to include study work, basic and detailed engineering, and expansion and repair projects throughout the life of the system.
The steel pipeline was designed for the transportation of a maximum of 1.4 million tonnes per year (Mt/y) of copper and zinc concentrates from the Antamina mine site in Northern Peru (elevation 4,100 metres above sea level) to terminal facilities at Huarmey.
The pipeline system includes:
Our comprehensive feasibility study for the initial project included route planning, pipeline constructability evaluation, detailed conceptual design, and a corresponding ±15% cost estimate.
After completing the study in 1989, we went on to provide basic and detailed engineering, procurement support, construction supervision, commissioning, operator training, and operations support.
Our control systems group also provided a complete turnkey package for the supervisory control and data acquisition (SCADA) system under contract with CMA and the telecommunications system under contract with Bechtel International.
The SCADA system consists of ten sites spread along the pipeline. Central control is available from either end of the pipeline. The system is based on Allen-Bradley PLCs as well as Wonderware Intouch HMI software.
Communication is via a Nortel Network SONET fibre optic network, using Ethernet and TCP/IP protocols. The fibre optic network, which has redundant fibres and a radio backup channel, also carries voice, data and video for the project.
The pipeline system was commissioned in 2001.
We subsequently performed a variety of studies and projects for the client, including:
In 2002, we performed a preliminary study using Pipeline Simulator™, to determine whether it would be feasible to transport lead and bismuth slurry with the existing pipeline system.
We determined that it was feasible if the slurry batch was limited to one hour, and we recommended a test loop program followed by tests in the mainline.
In 2006, we performed an analysis of pipeline performance, operating procedures, overall system condition, the pipeline emergency contingency plan, and possible modifications for the reduction of pipeline water consumption.
SAG mill bypass pipeline
In 2007, when CMA was considering a project to increase ore production from 30.2 to 38.8 Mt/y, we were selected to develop a conceptual study for a SAG mill ore bypass pipeline.
In this project, run-of-mine (ROM) ore material would be screened for fine material suitable to bypass the SAG mill. The fine material would then be fed from the mine site directly into the existing ball mills located in the concentrator area.
We evaluated two material handling concepts for the fine ore circuit; one with a grinding process and one without. Both concepts utilised screens to classify ROM ore and thickening to prepare the material for pipeline transportation.
We determined that the concept without the grinding process was not feasible, as the particle size distribution was not practical for pipeline transportation. Instead, we recommended the option which employed a ball mill and cyclone to grind the ore to a top particle size of 0.833 mm.
Our conceptual design included agitated storage tanks upstream of the bypass line; pumping system; main pipe and ancillary facilities; and agitated storage tanks downstream of the bypass line.
The project was completed in three months.
Coarse ore transport
In 2008, CMA wanted to add a new coarse ore pumping application to Antamina’s grinding facilities. The new system was intended to maintain operations in the event of a SAG mill shutdown.
CMA had already purchased pumps for the proposed application. Our scope included verifying that the pumps were appropriate for the project; hydraulic design of a transport system from the transfer tank to the ball mill feed tank; providing operating guidelines to minimise the risk of pipeline plugging; providing alternative solutions for material transport; and system sizing and recommendations.
In 2009, CMA retained Ausenco again to perform stress modeling and analysis due to concerns based on movements in the locality of a section of pipeline located at road kilometre 27 and pipeline kilometre 85 which is paralleled by a number of seismic faults. The goal of the project was to determine whether the pipeline was overstressed and if trench remedial works were required.
We also performed laboratory testing to determine the cause of an internal liner disbondment/ failure for a terminal station pipe spool. A technical report was prepared to describe the liner failure causes and provide recommendations.
In late 2009, a portion of the concentrate pipeline was damaged by an excavator working on the Pativilca-Huaraz highway.
Our scope in the repair project included the initial site investigation and preliminary damage assessment, initial diagnostic report, coating repair procedure, coordination of the repair work, and repair work supervision.
We completed the project in one week and provided a final report including quality certificates.