The mining industry is transitioning into the digital age. Miners are the most critical assets of any mine. They are initially being integrated into mines’ digital systems via their Cap Lamp since it is the only electronic device to be carried by every miner at all times. Today’s Cap Lamps have transformed from simple illumination devices to IoT (Internet-of-Things) Cap Lamps with tracking and communication capabilities. However, by design, a Cap Lamp has limited user inputs. The only way for the control room to communicate to miners is via flashing lights, which we call “signals”. These flash signals could represent warnings, general alerts or confirmations and acknowledgements.
Currently, there are two systems of signalling Cap Lamps. The first is two-way signalling on a networked Cap Lamp. The control room can send emergency evacuation calls to miners via rapid fast flashes on Cap Lamps. The control room can also page miners by sending slow flashes. Miners can acknowledge that they have received these alerts by pressing the button on their lamps. The second system is the V2P Collision Warning System (CWS) Cap Lamps. When a vehicle enters the CWS zone of a miner, the Cap Lamp slow flashes. As the vehicle gets closer, the flashes become faster. However, signalling complications begin to arise when you combine both systems. How do you differentiate between a page and far CWS signal or an emergency evacuation call and a near CWS signal? So far, Cap Lamp manufacturers have struggled to incorporate both signalling systems into a single Cap Lamp. To make matters more complicated, a single Cap Lamp can have multiple communication technologies built in. For example, some of Roobuck’s IoT Cap Lamps have both Wi-Fi and LTE for networking and sending emergency alerts and pages. It also has uses DSRC (Dedicated Short-Range Communications) or UWB (Ultra-Wideband) as part of its CWS. Furthermore, it can use BLE (Bluetooth Low Energy), RFID (Radio Frequency ID) or Wi-Fi for access control area management and equipment identification. All these functions could be sending signals to miners at the same time. When binary flash signals become too complicated, miners might as well be learning morse code. This is when flashing signal management becomes critical.
Effective management must consider the following six signals:
Here is a series of guidelines to make flash signal systems simple, practical and effective:
The following is a signal assignment example based on the above guidelines.
Message | Alert Level | Response Speed | Flash Signal |
Collision Avoidance (Near) | Highest | Fastest | Continuous fast flashes |
Collision Avoidance (Far) | Highest | Fastest | Continuous burst flickers |
Emergency Alert (Evacuation) | High | Fast | Continuous oscillating brightness |
Paging | Medium | Medium | Continuous low frequency flickers |
Hazard Area Warning | Medium | Slow | 3 slow flashes |
Confirmations & Acknowledgements | Low | Not required | 3 slow flashes |
This signal assignment was developed through comprehensive research and in-depth experiments which indicated multiple challenging situations that needed to be accounted for in the design. For example, what happens when multiple Cap Lamps flash simultaneously, but out of sync? What signals are used in similar real-world situations? How do we make sure CWS signals override all other signals? How does environmental lighting affect signal visibility? What are the possible dangers when signals are misinterpreted?
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