Commitment to delivering value-added projects - Compiled by Moses Chege Kasaija
Commitment to delivering value
Newmont Ghana Gold Limited (NGGL), a subsidiary of Newmont Mining Corporation, operates two mining projects in the Brong-Ahafo region of Ghana, approximately 290 km northwest of Accra. These two projects, namely the Ahafo Amoma project and the Akyem project, comprise 20 percent of the company’s core assets worldwide.
Over five years ago, Newmont Gold Ghana Limited (NGGL) set about conceptualising the development of its fourth and last pit in the Ahafo South permitted mining area. The Ahafo Amoma pit, is a greenfields opencast, gold cyanide-processing mining site.
The development of the Ahafo Amoma necessitated the detailed design, engineering and construction of all infrastructure related to the pit. Golder Associates was chosen as the contractor of choice to carry out this work. Golder secured the contract, in part, as a result of previous work completed for NGGL in Ghana by Golder’s Stakeholder Engagement team.
Golder’s involvement in NGGL’s Ahafo Amoma project began during stage three and involved the design, engineering and construction of a large majority of the infrastructure related to the gold-bearing, open-cast pit.
From the outset, Golder engineers added value by determining more efficient ways of setting up the project, whereby they reviewed and optimised NGGL’s initial design concepts. By starting the project on a good footing, Golder engineers could focus their attention to the project at hand. Included in the scope of work was the design, engineering and associated infrastructure, the waste rock dump and the Sedimentation Control Structures (SCS) and associated controlled outlet structure.
With no pre-existing roads or paths leading in or out of the Ahafo Amoma site, Golder, in conjunction with Richard Wessenberg (Golder USA) and Windhoek Consulting Engineers (Namibia), was required to design, engineer and construct a 25 metre-wide and 8,7 kilometre-long haul road from the Ahafo Amoma pit to the existing Ahafo South Run of Mill (ROM) platform.
The construction of this particular haul road, compared to a standard tar/dirt road, is quite different in that there are different load and surfacing considerations. The Ahafo Amoma haul road had to be designed and engineered to carry the load and size of large dump trucks, each weighing up to 200 tons.
In addition to the load considerations, the haul road had to be surfaced to withstand Ghana’s heavy rainfall seasons during April, May and June. As a result, the water management and associated drainage was a key element in the design and construction of the haul road.
The site’s secluded location, extreme topography and adverse weather conditions presented Golder with numerous challenges. These came in the form of logistics, water management, sedimentation control, security, and various others. Golder managed these challenges by thinking outside of the box, which involved extensive research and inventive in-house engineering, which well exceeded client expectations.
Furthermore, as the Ahafo Amoma site is located in a tropical area, water management and sediment control is a critical aspect to the overall functioning of the mine. As is common in tropical environments, the Brong-Ahafo region experiences frequent high-intensity rainfall events, resulting in significant erosion and sedimentation challenges, such as stormwater runoff containing large amounts of extremely fine material and silt.
Environmental laws in Ghana prohibit the discharge of silt-laden water into the surrounding river systems. As a result, NGGL required Golder to come up with a solution for the collection and conveyance of this contaminated stormwater.
Golder determined that a Sedimentation Control Structure (SCS) dam would be the ideal solution, and as a result, designed, engineered and constructed a 200 000 m3 dam. The SCS dam is designed to collect all stormwater from within the demarcated mine area. The stormwater contains silt particles which are merely in suspension as they are too fine to settle out of the water body. According to legislation, these silt particles have to be flocculated and removed or separated from the water, before the water can be released back into the environment.
During the course of the project, Golder Associates Africa presented NGGL with a series of risk workshops. With safety at top-of-mind, Golder developed a risk programme that looked into every aspect surrounding the Ahafo Amoma project, including health and safety risks and considerations concerning road crossings, pedestrians, power lines, etc.
The risk workshop supported Golder’s aim to be an industry leader in health safety, by creating a culture whereby health and safety is considered first and embedded in how both Golder’s employees and its clients work.
Golder’s ‘above and beyond’ work ethic and quality engineering and delivery of the Ahafo Amoma project, enabled NGGL to begin operations at the mine three months ahead of the expected operational date.
As part of its ongoing strategy to develop local talent in the regions that it operates in, Golder enlisted the help of three young Ghanaian civil engineers on the Ahafo Amoma project.
Prempeh Owusu, Dorcas Ankomah and Philip Asabere Kwame all studied civil engineering at the Nkrumah University of Science and Technology in Kumasi, a city in the southern central Ashanti region of Ghana.
Upon completion of their degrees and with majors in geotechnical engineering, the three engineers spent a year on site at the Ahafo Amoma project, as part of the National Service Scheme under the guidance of the project’s lead contractor Wilson Baily Holmes-Ovcon (WBHO).
Delivery of the Ahafo Amoma project to NGGL, both US$9-million under budget and three months ahead of schedule, epitomises Golder Associates in Africa’s readiness to deliver value-added projects to its clients.
By taking ownership of the project from the initial optimisation of design concepts during stage three, right through to the upskilling and mentoring of local engineers, Golder’s commitment to delivering value-added projects and quality engineering and delivery is evident in this project.
Golder managed not only to meet and exceed client expectations and deadlines throughout the project, but its ingenuity and originality in certain designs, such as the outlet structure in the SCS, has set a benchmark in sedimentation control.
The efficiency of this outlet design has resulted in Newmont Mining Corporation requesting Golder’s input in future international projects, specifically using its controlled outlet structure design.
Golder’s Integrated Project Management (IPM) team managed the actual coordination of the various Golder divisions and individual specialist engineers working on the project. IPM’s involvement in the project was a real value-add service to NGGL through the synchronisation of the various engineering disciplines, which resulted in one comprehensive report, instead of multiple disjointed reports.
Golder’s penchant to go over and above what is expected of them as set out in the contract, resulted in a project that is set up for success.