Tag Archives: Whittle

Deswik opens pit design options for miners with SPD module

Deswik says it has come up with a way to rapidly create practical pit designs from optimisation outputs as part of miners’ strategic planning process with its Strategic Pit Design (Deswik.SPD) module.

Developed in direct response to client needs, Deswik.SPD allows users to quickly generate multiple pit designs for any number of optimisation runs, compare results and select go-forward cases, the software company says. Final pit designs, which took days to create manually, can now be created in minutes, enabling planners to spend less time doing repetitive design tasks and more time analysing results and evaluating options.

Deswik.SPD features the Automated Pit Design tool, which bridges the gap between optimisation shells and a detailed manual pit design. The tool uses a scenario-based approach to rapidly generate, visualise and compare pit designs using outputs from Deswik.GO, Pseudoflow or other pit optimisation software such as Whittle, the company says.

The tool is flexible and, according to Dewsik, able to provide the following features:

  • Supports multiple ramp rules, exclusion zones and geotechnical domains for wall angle and berm width rules;
  • Provides post-processing options to smooth pit designs; and
  • Integrates with Deswik’s manual pit design and reserving tools, for more detailed scheduling, or to pass back into Deswik.GO for high level phase-bench schedules.

Any number of scenarios can be created with Deswik.SPD, according to the company.

Once processing is complete, the output designs are summarised in a table in rank order for review. Furthermore, if the results are not optimal, users can fine-tune options to manually adjust the output designs. There are also options to add a new ramp chain, move ramp chains to close large gaps, add switchbacks, manually adjust the berm shape and split ramps in two.

Tim Rijsdijk, from Glencore’s copper division, said Deswik.SPD produces multiple pit designs in the time it takes a mining engineer to design a single bench.

“By having a multitude of pit designs provided by Deswik.SPD, our mine planning team has been able to tactically implement the most suitable design and consider concepts that could often be overlooked when completing only a single design,” he said.

“Deswik.SPD also allows us to customise inputs that result in practical designs complying with site specific requirements, such as block model-based berm and batter parameters, dynamic ramp widths and gradients, ramp exit positions and exclusions zones. It has eliminated hundreds of hours of pit design work and allowed us to focus on adding value in more opportune areas.”

B2Gold weighs up in-pit crushing and conveying as Fekola mine expansion economics stack up

B2Gold’s plan to expand its Fekola gold mine, in Mali, by 1.5 Mt/y could see an up to $56 million investment in additional excavators, trucks, drills, support equipment and wheel loaders, according to the latest project economic study.

The expansion study preliminary economic analysis showed the company could increase throughput to 7.5 Mt/y, from the current 6 Mt/y base rate, by injecting just under $50 million over a period of some 18 months for processing expansion and upgrades.

As currently envisioned, the processing upgrade would focus on increased ball mill power, with upgrades to other components including a new cyclone classification system, pebble crushers, and additional leach capacity to support the higher throughput and increase operability.

“Critical path items include ball mill motors and the lime slaker, both of which will be commissioned in Q3 (September quarter) 2020,” B2Gold said.

“In parallel with the expansion, B2Gold is studying the addition of a solar power plant, which would reduce operating costs and greenhouse gas emissions. The current on-site power plant has sufficient capacity to support the expanded processing throughput, with or without the solar plant.”

On top of this, the company would need to invest in its mining fleet.

The current mining fleet consists of four Caterpillar 6020B excavators with haul trucks, drills, and support equipment to match, and mines an average of 36 Mt/y. The Whittle study results currently indicate mining production rates ranging from 54 Mt/y to 76 Mt/y are optimal to support the expanded processing rates over the life of mine and optimise head grade during the period 2020-2024.

B2Gold said: “Increased production will be achieved with the addition of two to four excavators with corresponding trucks, drills, and support equipment. Large front-end loaders would also be included to maintain fleet flexibility.

“Mine fleet expansion timing and scale will be optimised during Q2 (June quarter) 2019 and will generally be equipment loan/lease financed over a five-year period. The study has included $28 million for expansion to 54 Mt/y and an additional $28 million (for a total of $56 million) to go to 76 Mt/y.

“In parallel with the Whittle study, B2Gold is reviewing in-pit crushing and conveying as a means to reduce operating costs and potentially implement tailings and waste co-disposal at the Fekola mine.”

The expansion study estimated optimised that the life of mine could extend into 2030, including significant estimated increases in average annual gold production to over 550,000 oz/y during the five-year period 2020-2024 and over 400,000 oz/y over the life of mine (2019-2030).

This would see an increase in project net present value of approximately $500 million versus the comparable amounts in the company’s latest AIF mineral reserve life of mine model based on a $1,300/oz gold price and a discount rate of 5%.