Two unrelated mining projects — one in Colombia, the other in China — have led mining industry stalwart MMD to announce a revolutionary new approach to truck-shovel mining.
As the mining industry increasingly recognises the need for greater sustainability and safety, MMD’s latest concept has generated significant interest – offering mines the benefits of continuous mining with their existing truck fleet, where conveyor installation is impractical or too expensive.
Several years ago, MMD installed a Heavy Duty Apron Plate Feeder at a Colombian coal mine, which accepted loads directly from a dragline. The mine could not invest in a shovel because it would take too long to get the equipment onsite. The new system saw trucks queue under a controlled hydraulic feeder unit — loading trucks more accurately (sometimes up to 98 per cent) and more quickly (an average of 75 seconds).
More recently, in China MMD’s flagship Fully Mobile Sizer has proved the benefits of a direct partnership with the shovel, allowing material to be continuously loaded into its receiving hopper before being sized and discharged onto a face conveyor. Since the hopper capacity of the station is greater than the cycle time of the shovel, the shovel operator is unable to overwhelm the system.
During early site acceptance testing in China, MMD observed the shovel operator loading the hopper easily without ceasing. During certain periods, peaks of up to 12,000 tonnes an hour were witnessed — a much higher level compared to loading trucks in a traditional fashion. A shovel’s utilisation is often only around 60 per cent of what it could be and typically sustains less than 6,000 tonnes an hour, as it waits for trucks to return and spot.
MMD realised it would be possible to design a system that combined the benefits of both operations in China and Colombia for mines that couldn’t install conveyors, but wanted to mine in a more effective and efficient manner.
The Fully Mobile Surge Loader concept was born, with the option of the unit either working directly with a Fully Mobile Sizer (delivering sized hard rock or wet and sticky ores into the waiting trucks) or independently, directly between the shovel and haul trucks – beneficial for moving high volumes of overburden. Track-mounted, the unit is able to advance wherever the Fully Mobile Sizer or shovel go.
A significant benefit of this new approach is the ability to increase shovel utilisation to nearly 95 per cent: trucks no longer need to reverse into position, thus shovel waiting time is cut. Automated start/stop delivery of material into the truck from the feeder increases the fill factor and ultimately means fewer trucks are needed. The truck can sense the load and signal the feeder to stop at full payload. With a full hopper on the Fully Mobile Surge Loader, the shovel can reposition without hindering truck loading.
Additional key features include:
- Reduced truck body wear
- Reduced truck spotting time
- Hopper processing capacity greater than the cycle time of the shovel
- Minimal capital investment for significant improvements
- Enhanced mine safety
Distanced from the shovel operation, the working environment for truck drivers becomes safer and more controlled as they are separated from the swinging shovel bucket and direct loading impact of oversize lumps.
MMD envisions large open pit mines deploying several Surge Loaders to facilitate mining on multiple benches, with the Fully Mobile Sizer and Surge Loader for ore processing and individual Surge Loaders with each shovel to handle overburden.
Based on simulation data, five of these systems could do the work of seven shovels, which means capital outlay is reduced. Equally, fewer trucks are required to move the same amount of dirt.
For more information please visit: