In-pit mobility

More than half of the operating cost of mining is moving ore and waste around. So where autonomous trucks and drills are part of Rio Tinto's development programme, Vale's Serre Sul mine in Brazil has chosen IPCC. A conveying concept from FLSmidth, originally developed for oil-sands, is attracting attention.

Paul Emerson is not in doubt; in-pit crushing and conveying (IPCC) is not only the most efficient way of removing overburden it is a trend. Mining Magazine agrees; they awarded FLSmidth's Coffer Dam Concept, a concept for semi-mobile sizing stations, most innovative transport.

“Before the financial crisis the industry was in a rush to supplement their trucks with IPCC solutions; not to reduce the operating cost, but to increase production throughput, and reduce traffic congestion, in a period when availability of new trucks, and even more so tires and parts, was a challenge,” Paul Emerson admits. He is the Global Product Director for Minerals Material Handling solutions in FLSmidth and according to him, industry interest in low-energy transport is returning with renewed interest.

No hands no frills transport

The advantage of IPCC over traditional trucks is lower long-term costs. A single haul truck not only has a big up-front expense, but high operational expenses for tires, fuel and maintenance as well as a large supporting infrastructure and operating personnel. While IPCC also requires an up-front expenditure, the solution has minimal downtime and lost production – and the system doesn’t need constant monitoring. Fewer trucks also means less noise and dust pollution, less carbon footprint from lower energy consumption and related emissions, as well as a reduction in water consumption used for dust control. By reducing operating personnel and truck congestion in pits, safety is improved.

“For miners set on increasing productivity, transport costs are very prominent on the operational budget," Emerson explains. To increase productivity, miners must improve two of three variables: Capital investment, operating cost, and throughput: “It is tempting to increase throughput by adding trucks and shovels to existing fleets and infrastructure, but ignoring the long term operational costs will be detrimental in the new norm for the mining sector," Emerson predicts.

The Coffer Dam Concept

The Coffer Dam Concept, using semi-mobile sizing stations, is simple, low capital investment and operating cost-effective. The concept eliminates the need for costly retaining walls associated with large semi-mobile or relocatable stations. In essence, the concept is a system of specially designed and fabricated steel panels that make up a floor and retaining wall. These walls are erected within a simple key cut in a bench, and the earth is backfilled and compacted around it. The solution is designed to take all the associated loads of the earth and trucks feeding a semi-mobile station that is moved in using a crawler transporter after the box retaining wall and floor has been assembled.

Dual Truck Mobile Sizer is the only truck fed mobile sizer station developed in the market that can be fed by Ultra Class Mine trucks (400 ton payload)

Dual Truck Mobile Sizer is the only truck fed mobile sizer station developed in the market that can be fed by Ultra Class Mine trucks (400 ton payload)

Improved operating costs, environment and safety

  • Reduced downtime: Two low cost sets of panels can be used and alternated between moves, making downtime and relocation of large stations fast and effective.
  • Reduced costs: The cost of concrete retaining walls commonly in place at mine sites makes more frequent relocations of the stations cost prohibitive. Two sets of stationary retaining walls cost around 20% of the equivalent concrete set up, but are reuseable with every relocation. By reducing the number of trucks, costs for fuel, labour and maintenance associated with hauling material over long distances will also be reduced.
  • Reduced carbon footprint: Fewer trucks on site results in reduced dust and noise pollution, reduced fuel consumption and emissions, lower energy consumption and less water consumption (wetting of roads for dust control).
  • Improved Safety: By reducing trucks or replacing them with crushing and conveying systems, many safety incidents can be eliminated or reduced simply by having fewer truck operators on the roadways within, to and from a mine site as well as minimizing injuries related to truck maintenance and operation.
FLSmidth is commissioning this QB4 system at Cananea mine in Mexico for Groupo Mexico. The system is conveying 12,000 tph of crushed copper ore onto their permanent leach pad. This is the largest copper heap leachy stacking system in the world to date topping Radomir Tomic (11,500tph) also built by FLSmidth.

FLSmidth is commissioning this QB4 system at Cananea mine in Mexico for Groupo Mexico. The system is conveying 12,000 tph of crushed copper ore onto their permanent leach pad. This is the largest copper heap leachy stacking system in the world to date topping Radomir Tomic (11,500tph) also built by FLSmidth.

Contact: Paul Emerson, Global Product Director for Minerals Material Handling solutions, FLSmidth: Paul.Emerson@flsmidth.com