Regulations implemented by government authorities, including municipalities and environmental bodies, are impacting significantly on productivity in the global mining industry at a time when opencast operations are running at tight margins, says Johannesburg-based mining equipment manufacturer Vermeer Equipment Suppliers sales and technical manager Gareth Cramond.
Dust is a challenge on many mine sites, owing to urban encroachment and air quality concerns, he tells Mining Weekly.
“To date, in our market, most restrictions on opencast mines are being imposed by local authorities. “However, an increasing awareness of environmental, health and safety aspects around the traditional drilling and blasting practices has certainly driven a demand for alternative methods,” he outlines.
One solution that contributes to a more environment-friendly and safer mining operation, is the Vermeer T1255III Terrain Leveler surface excavation machine (SEM), enthuses Cramond, adding that it is also especially ideal for use in surface mine applications that have to deal with drill and blast restrictions.
Available to the South African market through Vermeer Equipment Suppliers since early 2017, the Terrain Leveler SEM features an optional dust-suppression system, a global positioning system (GPS) steering and grade control, as well as a cutting-head attachment.
“The optional dust-suppression system on the Vermeer Terrain Leveler SEM features an enclosed cutting head, with two large vacuums pulling dust from the enclosed cutting head into baghouses,” Cramond notes.
The collected dust is dropped beneath the machine, which helps reduce the amount of dust entering the air while diminishing the need to source water for dust suppression purposes during the mining process.
The Terrain Leveler SEM has a fully hydrostatic motor mounted to the side of the cutting head, which provides direct-drive power for the cutting drum. This configuration results in greater horsepower availability for the cutting of rock, enhancing efficiency when working in hard-rock conditions.
In addition, the direct-drive drum enables a quarry operator to cut an 80º high wall, which provides the required slope stability for high-wall mining applications.
Vermeer also offers a chain-drive drum, which enables a quarry operator to cut a 90º high wall and is also designed to work in hard-rock conditions.
Other advantages of the Vermeer T1255III Terrain Leveler SEM technology include access to areas of surface mines where drilling and blasting cannot be done because of physical or permit limitations, as well as a reduction in noise for dust and vibration, compared with drilling and blasting operations.
The machine also produces a smaller, more consistent particle size, which helps eliminate the primary crusher step; it can also be used for haul road construction and maintenance.
The SEM enables mines to excavate reserves they could not have accessed otherwise, owing to drill and blast restrictions or air-quality regulations, says Iowa, US-based Vermeer Manufacturing Company senior commercialisation manager for mining Patrick Robinson.
He explains that mines have spent considerable time and money on permitting, and that, by integrating Vermeer’s surface excavation technology with their drill-and-blast programmes, these mines can extract those reserves that might otherwise have been left in the ground.
The SEM features a patented tilt-head milling attachment with a top-down cutting action that can dig up to 55 cm deep and 365 cm wide in a single pass. As the unit travels forward and the drum rotates, the teeth on top of the drum advance, cutting into the mineral surface.
Operators can also control material sizing by increasing or decreasing the tooth penetration to produce a product less than 250 mm, while a uniform product size allows for more efficient operating settings to be employed on secondary and tertiary crushing systems.
GPS Technology, Autonomous Control
Cramond tells Mining Weekly that there are several GPS-controlled surface miners in operation on the African continent at various bauxite, coal and copper mines.
“We do foresee a further uptake of this technology since mining companies and contractors are seeking better solutions for their operations.”
The T1255III Terrain Leveler SEM features an optional GPS technology that can be used to create a mine-by-line plan – a mine plan can be uploaded to the GPS system and the machine will automatically cut to the plan, improving selective mining.
“This selective mining results in higher product quality, as you can separate lower and higher grades from each other. It enables one to mine thin seams at maximum cost efficiencies, owing to the ability to vary the cutting depth and angle.
“Machine steering is controlled by the GPS technology, helping to remove human error for cutting-head overlap and increasing the efficiency of the machine,” says Robinson, adding that the GPS system provides overlap cutting of 15.2 cm.
A patented tilt cutting head – which is tied to the GPS technology – enables the operator to control the cutting head depth and pitch. This feature also enables the operator to cut to the mine plan, producing a flat, almost road-smooth surface, a grade for drainage or a sloped haul road.
The technology also eliminates rapid changes in cutting depth, which can impact on productivity, and provides more precise cutting than an operator-controlled system.
The T1255III is also equipped with Vermeer SmartTEC control software that assists operators with adjustments to the machine operation to help improve machine performance.
“Our SmartTEC system displays the status of the many critical elements of a machine’s performance, with prompts providing visual cues to the operator for recommended control adjustment,” says Robinson, adding that the software also monitors and records various attributes of an SEM’s operation for future analysis by its owner or a fleet manager.
In addition, the Terrain Leveler SEM has a pressurised cab with a filtered air system to provide an increased level of operator comfort. The SEM can also be equipped with an optional full-function wireless remote, which enables the operator to run the machine from a safe distance if the project requires cutting against a high wall.
“The SEMs are available with a rollover protective module and a falling-object protective structure for when work is conducted near a high pit wall,” Cramond adds, noting that the machine’s low centre of gravity helps maintain its stability.