February 2008

Engineering Exchange

Klohn Crippen Berger Ltd: setting benchmarks for mining in BC

By H. Weldon

Construction underway at Ruby Creek

Adanac Molybdenum Corporation’s Ruby Creek molybdenum project has recently received the Environmental Assessment Certificate and required permitting to begin construction at the project site in northern British Columbia. The proposed open pit mine has a 22-year life at a production rate of 20,000 tonnes per day, and is the largest molybdenum mine to be approved in British Columbia in recent years.

Vancouver consultants Klohn Crippen Berger Ltd. celebrate this accomplishment with Adanac. KCBL was retained by Adanac to provide the engineering and environmental services necessary to obtain the EAC and construction permits, required for the project construction.

Adhering to Adanac’s high environmental standard, KCBL developed several new engineering and environmental solutions to the project’s many unique challenges. The innovations used to lessen the impact of the mine on the environment have quite possibly set a new benchmark for the mining industry in British Columbia.

Under the direction of Howard Plewes, principal, the KCBL team of engineers faced the challenge of designing the project’s tailings and water management facilities within the narrow confines of the Ruby Creek valley.

Key features of the design include:

  • Adjusting the location of the tailings dam to accommodate physical features of the valley, including basalt flows from the ancient Ruby Mountain volcano.
  • The non-acid generating characteristics of the tailings. This enabled the use of a cyclone dam in the tailings design. “It was a welcome part of the project, as KCBL has 40 years of experience using cyclone dam technology,” said Plewes.
  • Dump locations for waste rock are strategically placed in the confines of the Ruby Creek valley to minimize the footprint of the mine.
  • Ten kilometres of surface water diversions to pass clean water from the Ruby Creek catchment around the waste dump and tailings facility.

Brian James, manager of the environmental group at KCBL, is the project manager for the Ruby Creek project. The environmental component of this project is quite significant. “We faced many challenges,” Brian explained, “encompassing wildlife baseline assessments, noise modelling, fish habitat compensation and soil erosion prediction modelling.”

In a project this large, there are typically a large and diverse group of stakeholders. As part of Adanac’s commitment to open communication with the stakeholders, KCBL participated in a unique approach to the stakeholder consultation process, through extensive work with the Ruby Creek working groups for fisheries, wildlife and geochemistry. The working groups facilitated a unique collaborative forum where the interests and concerns of the stakeholders were openly discussed and addressed. “The use of collaborative working groups during the EAC phase of the project was really new and innovative, not to mention extremely successful,” James proudly explained.

An innovative approach to noise modelling was developed by KCBL in collaboration with the Wildlife Working Group to determine the effects of daily background noise on local wildlife. Impact of noise on local communities and worksite employees has typically been modelled in the past, however, little consideration has been given to the impact of noise on local wildlife. Through use of the model, impacts to caribou calving and sheep lambing periods were estimated. As a result, restricted blasting schedules were developed to minimize the effects of noise and vibrations during these periods.

Another unique environmental component of the project is the design and use of groundwater spawning channels for the Arctic grayling species as part of a fish habitat compensation plan. As very little is known about Arctic grayling, extensive baseline surveys were conducted by KCBL biologists, who found that grayling preferred existing groundwater channels over open streams for spawning habitat. Once constructed, the groundwater spawning channels will be the first used for Arctic grayling in British Columbia.

Erosion control and sediment retention was a key issue for project development due to the steep slopes and mountainous terrain. To overcome this challenge, KCBL scientists used a revised universal soil loss equation, commonly used for agricultural purposes to predict and create an erosion control adaptive management plan.

In summary, KCBL has successfully obtained the Environmental Assessment Certificate and regulatory permitting required to initiate construction. KCBL has not only complied with regulatory legislation and permits, but has gone beyond meeting these requirements in setting a high standard for environmentally and socially conscientious mining in British Columbia. KCBL plans to continue provision of integrated social, environmental and engineering services through project construction, operations and post closure.

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