|No matter how advanced mining machinery becomes, reducing the risk of unintentional interaction between miner and machine continues to be a vital component of safety. Each year, the industry reports injuries and even deaths due to unsafe contact with mobile equipment.
In response, a range of proximity detection technologies and collision avoidance solutions have emerged on the market over the years, all in an effort to reduce – and hopefully eliminate – these hazards.
But how does a mine decide which one will be most suitable for its needs? Some questions to ask include:
Different mining operations and working environments require different levels of detection and safety, and in this blog, we look at the different technologies available now, reviewing the capabilities and highlighting a few pros and cons of each.
Cameras are easy to install and are relatively inexpensive; however, they are passive systems with no active detection or warnings, so to be effective, they rely on the machine operator to monitor the screen.
Radar systems provide a robust, reliable detection capability for object position and distance identification. With sensors installed on both the front and back, the direction of travel is irrelevant.
Since radar is subject to alarm triggers when any object enters its field – regardless of what that object is – benign objects could cause false detects and nuisance alarms, resulting in loss of efficiency and wasted caution for the operator. Cameras and display screens will typically become necessary at that point.
This lack of object discernment also makes radar less suitable for autonomous braking capabilities. Radar is alarm-only to the operator and does not warn personnel on foot.
RFID is a highly versatile, readily available technology that has the benefit of being cost-efficient as well. The systems are easy to install and work with any number of tags.
It can, however, be susceptible to interference, and the radio waves can be easily blocked. Since batteries are required to operate individual tags, a false sense of safety could result if the battery power isn’t checked regularly.
RFID can be an effective warning solution for machine operators, but typically pedestrians are not alerted.
Global Positioning Systems (GPS)
The primary benefit of using GPS to track workers and machines is accuracy; the technology is highly accurate and can be used to cover a very wide area. With the use of an on-dash display screen, it provides a 360° view of the machinery’s surroundings, including all other vehicles within a specified range.
A potential downside to GPS is that it only works with an unobstructed view of the sky. It can be affected by overhangs or highwalls and can also experience difficulties in canyons. GPS is also an alarm-only system, but can be programmed to alert all parties involved, including pedestrians, with the incorporation of RF.
A critical disadvantage with GPS is that it is not ideal for close-range proximity detection. Therefore, it is generally ineffective for start-ups, reverse operation and covering blind spots.
Ultra-Wide Band (UWB)
UWB offers the benefit of highly precise positioning, which allows operations to identify different levels of proximity zones such as “warning” or “hazard” zones.
UWB does experience multipath reflection, which in layman’s terms means the signals bounce or reflect off surrounding surfaces. Multipath benefits the system by ensuring that the signals are registered; however, it can alter the ToF calculations which could lead to erroneous position estimates of the objects.
When the warning zone is breached, parties receive audible and visual alarms, and if elected, the machine will automatically slow its speed. If the hazard zone is breached, the system will alarm and can be programmed to completely stop to avoid a collision. This interlocking capability ensures the highest level of personnel safety while working around operating machinery.
EM is unaffected by its environment and the atmosphere and can easily penetrate coal, rock, construction barriers, stoppings and ventilation curtains.
Electromagnetic systems are proven technology for “near field” hazards – meaning the fields are highly stable and the system works at extremely close range. It warns both equipment operators and personnel-on-foot simultaneously and can be interlocked into machinery controls to reliably slow or stop the machinery.
NO TWO ARE THE SAME.
Given the nature of the underground working environment, with factors such as low visibility, confined work areas, physical barriers and the heavy presence of mobile machinery, electromagnetic proximity detection has over the years been proven to be the most effective technology for these environments. The risks associated with working alongside mobile machinery underground are well known, and the requirements for the proximity detection systems have been defined.
The core technology of Strata’s HazardAvert® system is refined for these applications and has demonstrated high accuracy in close quarters. It has the capacity to function with hundreds of vehicles and pedestrians in close proximity without latency or delay.
Strata has over 1500 HazardAvert® systems currently active in both surface and underground mining environments, and in underground tunnelling operations around the world.
To learn more about Strata Proximity Detection go to the CONTACT tab or WEBSITE link below to reach Strata Worldwide directly.