Project delivery company WorleyParsons RSA has recently completed the Feasibility Study Update (FSU) for the Wafi-Golpu Joint Venture (WGJV) in Papua New Guinea, giving the greenfield Wafi-Golpu Project a revised execution plan going forward. Bryan Bailie, the Executive Project Director for WGJV says, “The Feasibility Study Update developed by the WGJV, WorleyParsons RSA and other consultants sets out an improved business case for the Wafi-Golpu Project, and the study confirms the preferred technical options to deliver the block cave mining project safely and with appropriate consideration given to environmental, social and cultural heritage stewardship.”
The FSU report incorporates findings from earlier Pre-Feasibility and Feasibility Studies and draws on extensive data collection undertaken since 2016, providing a deeper understanding of the project’s geotechnical, mining, processing, oceanographic, environmental and social parameters. It also forms an integral component of the revised Proposal for Development in support of the Special Mining Lease application which was submitted to the Mineral Resources Authority (MRA) by the Wafi-Golpu Joint Venture in August 2016.
Wafi-Golpu is a joint venture copper-gold project that is owned 50/50 by Harmony Gold Mining Company Ltd in South Africa and Newcrest Mining Ltd in Australia. It is located in the Morobe Province of Papua New Guinea, approximately 65 km south-west of the city of Lae.
Various approaches to development (including infrastructure configurations) have been considered in the investigations for the development of the Wafi-Golpu deposits. Early investigations considered large-scale open pit mining of the Wafi deposit rather than underground mining; however, this was dismissed for various reasons. Subsequent investigations were highly successful in more accurately delineating an orebody, but further work was required to determine the economic viability of mining. A number of technical studies across various disciplines were completed since 2012 which determined a viable business case for development of a large-scale deep-level block cave mine. The proposed development contemplated a significant upfront capital commitment to deliver maximum resource extraction and production profile over the project’s life.
The outcomes of the Pre-Feasibility Study initiated a Pre-Feasibility Optimisation Study phase of work. This phase of work contemplated alternative options focused more towards a smaller, scalable, lower capital cost start-up mine. In November 2013, the Pre-Feasibility Optimisation Study was commissioned with the purpose of developing a single, preferred business case to a pre-feasibility study level of definition. WorleyParsons RSA were appointed by the WGJV as the Pre-Feasibility Optimisation Study consultants. Prior to commencing the Pre-Feasibility Optimisation Study, WorleyParsons utilised the StepWise methodology to develop, assess and shortlist preferred options. The StepWise process, developed by WorleyParsons’ strategic and advisory arm Advisian, provides solid data to enable prospective funders to make strategic investment decisions, with a focus on maximising returns, while minimising and managing exposure to risk.
Bailie says that by following the StepWise process, the WGJV and WorleyParsons RSA were able to reframe a new business case for the Wafi-Golpu Project by looking at a small-scale build-up and programme of ongoing work that led to the feasibility study, and later the Feasibility Study Update.
Initially fourteen conceptual mining options were developed and assessed with the associated technical and business case, which was narrowed down to three preferred options to carry forward into the Pre-Feasibility Optimisation Study. WorleyParsons RSA completed the pre-feasibility optimisation study in 2014 which recommended a staged development approach involving the mass mining method, block caving, commencing with the development of a smaller lower cost start-up mine (Stage 1 Project). The Stage 2 Project focused on a life of mine plan as a follow-on from the Stage 1 Project, with the objective of identifying and evaluating options to maximise and enhance the value of the Golpu orebody through optimising access and the exploitation of the orebody above 4,100 m RL target area.
In 2016 the feasibility study was subjected to a competent independent review process which identified no fatal flaws but made recommendations for additional work to be undertaken. New legislation pertaining to changes in the fiscal and taxation regime had adversely impacted the economics of the project while tailings management developments, data from deep geotech drilling and concerns regarding power generation all necessitated the reconsideration of the initial pre-feasibility and feasibility studies.
Based on the orebody dataset improvement achieved in 2016, the Feasibility Study Update intended to validate, optimise and improve upon the 2015 Stage 2 Golpu Pre-Feasibility and Feasibility Study findings and recommendations.
The FSU incorporates a much larger mine than previously anticipated and mining throughput will be increased from 3 to 16.84 Mt/y at BC44, 6 to 16.84 Mt/y at BC42 and BC40 at PFS level. This increase in throughput required the redesign of the underground material handling system, process plant, associated infrastructure, and overland concentrate and tailings transport pipelines.
In setting out the updated business case for the FSU, WorleyParsons RSA drew on SmartPlant design technology that utilises rapid prototyping, and other innovative processes such as Building Information Modelling (BIM) to create a sophisticated digital project design platform and prepare for project execution as efficiently and cost effectively as possible.
“By utilising our intelligent design tools we were able to incorporate all the consultants and role players involved in the project into one user-friendly digital model,” says Senior Project Manager at WorleyParsons RSA Niell McEwan. He explains that SmartPlant is a powerful portfolio of design and data management solutions that captures integrated engineering knowledge to enable productivity gains and improving engineering efficiency and design productivity. It includes Building Information Modelling that augments the three primary spatial dimensions of width, height and depth with 3D, 4D and 5D technology, allowing the entire project team to visualise project objectives as never before, greatly improving operational efficiency in a dynamic time and cost-saving environment.
General Manager for Engineering and Construction for WGJV Leigh Cox adds that making use of the WorleyParsons RSA rapid prototyping, and other innovative processes such as Building Information Modelling, underpinned efficient engineering and design delivery with the added benefit of having higher confidence in the design, design integration and in cost estimation and planning. “We were impressed with WorleyParsons RSA’s use of BIM for the FSU as it showed us how quickly different components and disciplines can be merged together to help evaluate design, optimise resource utilisation and identify design risks upfront and on an ongoing basis,” says Cox.
The findings of the Feasibility Study Update provide greater clarity around the infrastructure which will be associated with development of the Wafi-Golpu Project and proposes a modular designed power plant to ensure a reliable base load power supply; new port facilities created within the Port of Lae; a new northern access road and two new community roads; and puts forward three types of tailings management options for consideration.
If developed, the Wafi-Golpu Project will be the largest, deepest and most complex underground mine in PNG, with a mine life of 28 years. As well as this significant injection into the PNG economy, the project will create economic benefits across the country, including around 2,500 direct jobs during construction, about 850 ongoing operations jobs and further indirect jobs created in the region.