Fatalities and injuries in mining not only affects the physical safety and well-being of workers, but it has the potential to bring operations to a halt – a risk to the job security of millions of workers in the mining industry.

The Safety Risks of Underground and Open-pit Mining

All too often news reports tell of tragic mining incidents, where employees get lost or injured and pass away before search parties can locate them. The risks are plentiful:

  • Large geographic areas in deep level underground mines make for miles of haulage systems and travelling ways, where employees could potentially get lost or injured.
  • Searches are normally initiated only once a shift clearance process has identified a person that has not clocked out prior to blasting times or ‘end of shift’ windows.
  • Mobilizing search teams and then trying to determine where to start looking can take several hours –time that is critical to the search and safe recovery of a lost or incapacitated employee.

The need for Lost Persons Detection Technology in Underground Mining

In 2006 Profitek’s Minelert identified the need for accurate location tracking systems, specifically for the mining industry, that could seamlessly integrate into existing wired- or wireless Ethernet backbones. Such integration would eliminate the administration and maintenance of multiple proprietary communication systems.

Real-time Location Systems (RTLS) for Enhancing Safety in Underground Mining

RTLS for mine safety

One of the technologies investigated was Real-time Location Systems (RTLS) which are primarily used in healthcare applications. RTLS provides immediate or real-time tracking for the management of medical equipment, staff and patients.

During research into this technology, Profitek’s Minelert found that there were two major RTLS players who dominated the field: Aeroscout and Ekahau. Both solutions claimed to be market leaders in WiFi based location systems and both of them used WiFi Access Points (AP) combined with WiFi active tags.

At its core, RTLS is dependent on triangulation of Access Points, thorough site survey to capture RSSI (Receiver Sensitivity Signal Indication) values and the upload of this data to the software positioning engine to accurately locate a tag with an accuracy of a few meters. These RTLS solutions also support Proximity/Presence modes in order to give an indication of tags located in the general vicinity of the Access Point.

Selection Process of RTLS Technology 

In order to find RTLS technology that would be suitable for the rugged industrial conditions of underground and open-pit mining, the following considerations were taken into account:

Aeroscout firmware is hardware dependent, since it can only be installed on selected certified Access Points in order for the specific Access Points to act as a zone within the RTLS system. Choke point detection hardware (Exciter) is required for proximity mode and operates on a 125kHz frequency. The maximum reading range of this system is 6m.

Ekahau utilizes software zoning within the positioning kernel and can be used with any available Acces Point. Additional Location Beacon hardware improves presence notification and utilizes infrared technology for a reading range of up to 1 meter (3 ft).

Challenges of RTLS Technology in Underground Mining

In a statement released this year Aeroscout announced that it will be discontinuing their industrial product line, effective 1 November 2015. As result of future unavailability of Aeroscout RTLS technology as well as technical specifications, Profitek’s Minelert selected Ekahau as solution for further research and development.

In partnership with Ekahau from 2006 to 2008, Profitek’s Minelert found numerous challenges in adapting the RTLS technology for mining applications.

  • Inconsistent tracking information made it very difficult to create a triangulation environment in mining haulages. The positioning engine was not able to accurately interpret and visualize the RSSI values of tags.
  • Implementation proved very complicated. Whenever there is a change in the mining environment, a new site survey is needed to reflect the changes in the position engine.
  • Poor tag battery performance made it a maintenance intensive option. When the beacon rate is set to 4 seconds, the tag’s battery life was reduced to 1 week.
  • Expensive technology. Both the tags as well as the software positioning engine were costly to acquire and maintain.

Profitek’s Minelert Contribution to Mine Safety Technology

In 2009 Profitek’s Minelert started active development of their own Lost Persons Detection System. The Profitek’s Minelert LPD system is a proximity (zoning) solution and is based on 2.45GHz technology that has been proven in search and rescue operations as well as underground tunnel applications around the world.

Since then Profitek’s Minelert has had numerous successful implementations in the mining industry in mines including AngloGold Ashanti, Harmony and Anglo Platinum.

A 2014 earthquake at one of AngloGold Ashanti’s shafts in South Africa put the Profitek’s Minelert Lost Persons Detection System to the ultimate test. Profitek’s Minelert passed with flying colours and Mike O’Hare, Chief Operating Officer, gave us this stirling customer review:

“Safely hoisting all 3,300 people to surface after an earthquake of this size is an achievement of which we’re immensely proud. Our infrastructure responded as it was designed to, and our safety protocols worked as they should. Our thanks go to every employee, the contractors on site and the management team who together made this outcome possible.”

Underground Mine Safety