Mining

Applications
Title	Mining
Author(s)	GMV.
Level	Medium
Year of Publication	2011

Satellite navigation has proven a significant increasing in productivity and improved on-site safety in mining activities, e.g., mineral and aggregate extraction with especial incidence in iron ore and coal extraction and transport tasks.

In open pit mining, accurate GNSS is useful for tasks such as machine guidance, grading, dozing, drilling, collision avoidance, surveying, and fleet management.

More advanced positioning technologies, such as local and regional Real Time Kinematics (RTK) systems increase the accuracy achieved to less than 10 cm, conducting to a large productivity increasing.

Application Architecture

Mining

Mining is often done at remote sites, which are difficult to monitor from a company's central control base. At the same time, any problems or failures with the large and expensive trucks and excavators need to be resolved fast to minimise downtime. This calls for good and reliable communication facilities.

The conventional coal mining surveying, positioning and monitoring approaches are both time-consuming and costly. With the introduction of GNSS based systems aims to increase the productive availability of ultra-heavy mining trucks, giant excavators and earthmovers that extract and transport mineral ore from open-cut mines to processing facilities in some of the most remote regions of the planet.

Accuracy

There are four basic levels of accuracy associated with GNSS:

1. Autonomous – 15 to 100 metres,
2. Differential (DGPS) – 0.5 to 5 metres,
3. Real Time Kinematic Float (RTK Float) – 20cm to 1 metre,
4. Real Time Kinematic Fixed (RTK Fixed) – 1cm to 5cm.

The most mining GPS systems are implemented as Differential GPS (DGPS). These systems require a reference station that acts as a base for the entire GPS network at the mine site. The corrections calculated are from the GPS coordinates compared to the known coordinates of the references station and are transmitted by the radio network to the equipments in the field.

Mining Operations

The GPS guidance systems are applied to many aspects of mining operation including:

• Blasthole Drilling: GNSS based blasthole drill systems provide drill monitoring, control and guidance. These systems consists of the following pieces of equipment: GPS receiver, GPS antenna, radio and radio antenna, cables, power supply, operator display, on-board computer, interfaces to third party software, sensors to monitor drill and aid in material recognition.

The prime objective of GPS positioning for drilling is to navigate the drill rig over the designed collar position, eliminating the need for manual survey.

• Shovels, Loaders, Dozers and Graders: This applications process the updated design of the mines, ore blocks, pits and roads, overlapping this map information with the vehicle's current positions. The topography is updated as the machine progresses into the face. The face position assists in forecasting and scheduling decisions to running an efficient operation. The on-board display highlights different colors for the operator knows when he is mining above or below the design floor grade.

• Vehicle Tracking and Dispatch: For mines dump trucks tasks DGPS accuracy is required. The dump trucks positions obtained are sent to the central control station, where is carried the dumping scheduling management.

This application determines which material is loaded and sends information and instructions to be followed by the truck drivers, in order to guarantee that the assignments are followed and the materials are correctly dumped.

• GPS Surveying: The basic pieces of equipment required for GPS surveying are: GPS receiver, GPS antenna, radio and radio antenna, lightweight batteries for power, cables, backpack, handheld data collector.

The advantage of using GNSS for surveying in open pit mining is that only a single surveyor is required, in opposition to the conventional methods.

• Monitor Drivers and Vehicles: The sensors in the vehicle provide monitoring information of equipment's, like for instance air pressures. These systems also provide sensors to analyze the operator's well-being, by measuring key body parameters such as heart rate and skin temperature. This information is combined with GNSS information and is sent to a central control station.

The huge haulage lorries are connected wirelessly to the mine's control centre and via satellite to a back office control centre for the machines and their drivers to be continuously monitored for rapid intervention in case of problems.

Application Characterization

GPS applications in the mining industry include the following features:

• Control of heavy machinery such as draglines,
• Control of bucket wheels and dozers,
• Drill guidance,
• Roads grading and maintenance,
• Fleet management systems for haul trucks and other vehicles tracking and dispatch,
• Asset tracking, for instance, of lighting plant and mobile generators,
• Guidance and control for drill rigs and explosive trucks,
• Access and zone control for visiting vehicles,
• Detecting dangerous driver behavior and
• Collision avoidance applications.
• Surveying crews can be reduced

Safety Applications

GNSS based applications for survey and machine guidance brings important safety benefits in the mining industry.

• Surveying: Most mines now use RTK systems for surveying. GNSS considerably speeds up the surveying process and reduces the time surveyors are in the field often in vulnerable locations, eliminating the process of establishing field control points eliminated.

• Truck Fleet Management: In a fleet management application, trucks can be assigned to different loading machines in real time to improve overall efficiency. A safety benefit is that the central control station always knows the location of each truck. Stand alone GPS is generally adequate for this task.

• High Precision Machine Control: This systems increase efficiency, eliminating the need to have people on the ground outside vehicles, where they are most vulnerable to accidents, and the eliminate the need to deploy pegs in the field.

The GNSS-based system record the positions that they have worked, eliminating the surveying procedures on the field, as well as the machine operator's surveying tasks. Blast hole drills can be set up without the need for surveyors, or the drillers to mark out each hole. On shovels and excavators, GPS systems can be set up to indicate the exact location of the bucket relative to the boundaries of the ore body or coal seam. In situations where the ore is not readily distinguishable from waste, this can save considerable field time for geologists and surveyors in marking out the ore body limits. Similarly in coal, the ability to selectively mine bands of different qualities is enhanced, again without surveyors on the ground. A safety benefit is the recording of events, which can be useful is accident situations, in order to obtain the causes that lead to the incident

• Hazard Avoidance: These applications warn the operator of site hazards. For example when machines are being maneuvered next to each other and the operators don't manage to see other due to terrain orography.

Another hazardous situation is encountered in many open pits where the deposit has been previously mined by underground methods. The numerous voids present a severe hazard to mining equipment and vehicles. A GNSS based system can avoid the operators about the dangerous zones. These systems can also be set to automatically broadcast an assistance required signal to the central control station, for instance if the device is tilted beyond a preset angle. For the accuracy required for this system Differential GPS is adequate, although an RTK system will offer substantial accuracy.

• Collision Avoidance: This systems must be included in all mining vehicles, which continuously report their position to the central control station, where the data is analysed and vehicles can be warned, if they are in collision course.

This type of architecture requires large bandwidth capabilities and is especially relevant in environments where light and heavy vehicles work side by side.

Application Examples

The following systems are among the most relevant in mining industry:

• Computer Aided Earthmoving System (CAES), by Caterpillar - Minestar
• Aquila Drill Management, by Caterpillar - MineStar
• WENCO System
• MODULAR System
• EstrellaSat, EstrellaSat enable a central control base to monitor machines and the people operating them at the company's excavation sites in real time. The system's touch screen for drivers, is mounted in the truck’s cabin. If a sensor indicates a lorry malfunction or potential driver fatigue, the remote operator opens a mobile broadband satellite link for face-to-face communication with the driver via the screen.

The following industry fields are using similar GNSS-based systems:

Gas and Oil Offshore Platforms

In offshore platforms field, there are also advanced tools to monitor remote gas and oil infrastructures using GNSS. These applications require very high precision, reliable and highly available positioning tools for the monitoring of subsidence. Remote user interface systems provides an intelligent and easy overview of a large number of monitored parameters.

Civil engineering

In civil engineering accuracy and reliability are essential. Combined with digital mapping, GNSS represents a powerful tool for reducing costs and increasing productivity while maintaining the highest construction standards, from the planning of structures to the maintenance and surveillance of existing infrastructure. Heavy equipments used in construction such as blades and buckets of construction, are automatically controlled in GNSS-based machine guidance systems.