Mining depends on the extraction of minerals from ore bodies. Whether surface or underground the ore body need to be fragmented to facilitate transport to the processing facility. While the basic process of drill and blast has not changed over the past century, there have been significant advances in the methodology that has led to improvements in operational efficiency and safety.
The ongoing improvements in information technology (IT), communication and sensing, termed the Internet of Things (IoT), has created opportunities for the integration of mining equipment and IT systems which can improve efficiency, reduce costs and increase revenue and reduce dependence on human intervention.
A number of field proven technologies are presently available which can be used to reduce costs and improve safety of blasting which will maximise the revenue from the operations. These are described in more detail below.
Bulk Explosives Silos
Bulk explosives such as ammonium nitrate emulsion (ANE) and ammonium nitrate porous prill (PPAN) are used by mobile manufacturing units (MMU) which formulate and load the explosive used for the blasting operation. The bulk explosives are often stored in silos close to the mine operations and need to be replenished based on usage. The available product in the silos, usage from the MMU’s and the capacity of the replenishment tanker are variables that need to be balanced to ensure the number of tanker trips meet the demand from the process.
This can be ensured by providing remote capacity monitoring of the stored explosives. The silo levels and usage rate are monitored at a central facility from which the tankers can be dispatched. This optimises the costs of replenishment and ensures the explosives loading process is not interrupted by insufficient product. A number of safety parameters can also be monitored by this system which improves the risk management of the storage facilities. TLC is able of supply remote monitoring and back-office equipment for the remote monitoring of bulk explosives silos.
In addition to the bulk explosives, a number of accessories are used in the blasting process. These include detonators, boosters and detonation cord. These are typically stored in explosives magazines where the blasting personnel can withdraw these for the operations. The control and inventory management of these sites is usually manual and can lead to a number of issues such as:
- Poor stock control
- Storage and issue of products past expiry
- Poor management of unused items.
Remote monitoring and control of explosives magazines can eliminate these issues at a nominal cost. TLC has a number of products that can be used to monitor the flow of products in and out of explosives magazines. TLC also represents ITS who have implemented comprehensive explosives tracking (cradle-to-grave) systems as shown below:
Mining efficiency is dependent on the mining cycle. Any delay in the time it takes to drill, load, blast and clean reduces productivity and consequently revenue. Mining equipment operates in harsh conditions and breakdowns are inevitable. However through advanced remote monitoring it is possible to detect signs of incipient failure so that preventative measures can be taken before a breakdown occurs. Remote monitoring systems can also assist in troubleshooting and even repairing equipment failures. Information collected from breakdowns and repairs can also be used to make product improvements. TLC has field proven equipment that can be used to monitor equipment performance and remotely communicate this to a management dashboard where it can be viewed and analysed.
Drill Hole Monitoring
Ground conditions can pose additional hazards to the loading of explosives. Reactive ground conditions and “hot holes” can result in the premature detonation of explosives with consequent injuries, damage to equipment and loss of life. The use of infra-red scanners is often used to indicate heat emanating from a drill hole but this only provides a snapshot of the present condition. The only effective monitoring method is to measure the drill hole temperature at a varying depths over a period of time. This data can either be manually or remotely downloaded and analysed to assess the risk and mitigation methods that should be used to ensure safe blasting. The records can also be used as part of the risk management and documentation process. TLC has compact battery powered data loggers for the monitoring and assessment of drill-hole conditions.
Blast Design Tools
O-Pitblast is a Blast Design and Optimisation Platform where you can plan your blasts on your computer (with all the tools available for that), share projects between coworkers or supervisors with the included cloud system and generate blast plans. On the pattern (field) you are able to control by our iPhone/Android app the drilling and loading procedure, generate Blast Reports (based on that real information) and export QAQC reports. Also included, is the fragmentation module (you can predict fragmentation and calibrate the model to your operation), the vibration module (where you can calculate automatically attenuation laws to your terrain) and the optimization module where you can generate blast designs that fulfill operation demands or reduce operation costs. TLC represents O-Pitblast in Southern Africa.
Blast Parameters Measurement and Optimization
Traditionally, face mapping has been measured with 3D laser scanners, but new data acquisition systems like 3D point clouds derived from stereo imaging systems and photographical methods which process data obtained from drones are becoming widely used. These methods generate large data sets with high levels of detail, in some cases even down to millimetre and centimetre accuracy. TLC has an application, Winprof, that rapidly processes this data and calculates hole spacings, front row burdens and prediction of flyrock effects. Examples of Winprof outputs are shown below:
- Velocity of Detonation (VOD). VOD measurements are used to check the explosive performance, to obtain the real initiation sequence and to identify the sources of peak particle velocity (PPV) pulses. VOD is typically measured using a sensor probe which is consumed during the blasting. The sensor probe can be made of a proprietary resistance wire or freely available, low cost coaxial cable using time domain reflectometry (TDR). Since up to 500m of cable are consumed at each blast, the cost of the sensor probe is a major factor in the cost of operation of VOD equipment. TLC has a locally developed TDR instrument for measurement of VOD, SpeedVOD, which uses low-cost coaxial cable. An example of a VOD result obtained using the SpeedVOD is shown below.
- Ground Vibration Prediction and Monitoring:
TLC has developed an application that uses blast hole vibration signatures to optimise blast pattern timing to ensure minimum vibration levels. The application uses actual blast hole coordinates and charging information to generate optimised timing information. The application predicts the vibration levels with the designer’s timing pattern and then provides an optimised solution as shown below.
PPV before Optimising
PPV after Optimising
TLC supplies high channel count instrumentation for measurement of critical vibration parameters of affected structures. This data is available remotely in real-time.
Drill Hole Measurement
Drill hole geometry is an important determinant in the quality of the blasting results achieved. The holes are drilled according to a blast design pattern to achieve the correct burden and spacing based on the geology, explosive selection and desired fragmentation. Instrumentation can be used to measure the key drill hole parameters including:
- Hole Depth
- Drill hole deviation
Most survey instruments will be able to perform only one function. However TLC has developed a borehole probe which is able to combine these measurements with a video camera to allow for inspection of the drill hole.
TLC Engineering Solutions has been working with mining companies, explosives suppliers and equipment manufacturers for over 30 years to provide design tools, instrumentation, measurement, monitoring and communications equipment to improve mining operational efficiency and safety. We are ISO9001:2015 registered, BBBEE Compliant and are a Microsoft Certified Partner, Microchip Design Partner and National Instruments Alliance Partner. For more information contact us at [email protected] or +27 87 808 2290.