The mining and tunnelling industry has developed rapidly during the last decades. On the one hand the global growth lead to an increased demand for raw materials and infrastructure projects. On the other hand, technical developments enable the development of new resources. Therefore, many opencast operations are going underground; existing underground operations are developing deeper resources; new mines are being developed in more challenging environments and tunnel construction is also facing increasingly complex tasks due to new infrastructure projects. These changing conditions result in new requirements for the safety of employees and installations as well as for the associated emergency services of these operating facilities. The latter applies in particular in the event of a fire or contamination which is accompanied by the unavoidable evacuation of people in an emergency situation and when appropriate measures and equipment are required to cover longer distances through the affected areas in order to reach and rescue these people.
Nowadays, mine rescue teams often have to walk with all their equipment and personal respiratory protection equipment during such events, which must be activated as soon as they enter a contaminated area. In doing so, they consume a higher proportion of the total breathing air reserves until reach of the emergency places. As a result, the longer they travel to these locations, the less air reserves and working time are available for the main rescue operations, such as locating people, taking first aid measures and carrying them to safe spots. Especially in case of crossing smoky tunnel sections with very limited visibility, this results in additional precious time resources at a time when every second usually counts.
After risk analysis of major mining companies, it became clear that reasonable demand for advanced mine rescue services have to come along with a significant increase in the operational productivity of the rescue teams and equipment. Based on the cooperation of specialists from Dräger and PAUS Maschinenfabrik GmbH, developments were started.
As a first result of the cooperation, the mine rescue vehicle MRV 9000 was developed in order to bring rescue teams in a self-contained and mine-proven mobile solution quickly and as close as possible to the emergency places. It‘s operational capability was achieved by combining the mine-proven designs of the basic chassis type MinCa 18A from PAUS and with the life support systems and further technologies from Dräger.
The life support system
The MRV 9000 provides an integrated life support system that allows mines rescuers to travel to and from the incident while providing safe and clean breathing air in a controlled environment.
The life support system is integrated into the vehicle. In purge mode, which is the standard during the most of the operation, the breathing air from the breathing air reservoir is constantly supplied to the driver’s cabin and the rescue cassette with help of the air management panels. With the help of these panels, the amount of air can be adjusted to the number of persons in the driver’s cabin and cassette. Approximately 40 l/min. per person is required to flush out excess carbon dioxide (CO2) or harmful gases through relief valves and replenish oxygen. Furthermore, the combination of the above-mentioned components of the life-support system results in an overpressure of at least 100 Pa in the air-tight driver’s cabin and the rescue cassette. This reliably prevents the penetration of harmful gases. Internal gas monitors continuously monitor the breathing air quality in both the driver’s cabin and rescue cassette.
During a rescue mission, members of the mines rescue team equipped with breathing protection must leave the MRV 9000 in order to address the mine emergency. At this time, harmful gases could enter the driver’s cabin and rescue cassette. To deal with this situation, the life support system is equipped with a flush mode which quickly increases the supply of breathing air from the breathing air storage to approximately 1000 l/min., thereby flushing out harmful gases. Once the integrated gas monitors indicate that the breathing air is safe again, the purge mode can be activated again. Personal breathing protection can be removed.
Special seals, doors and hatches ensure that the driver’s cabin and the rescue cassette are air-tight. All openings are designed to accommodate rescue personnel with the necessary breathing apparatus.
The mine rescue vehicle has enough room for two people in the driver’s cabin and six in the rescue cassette. All seats were specially designed allowing room to sit comfortably while wearing a breathing apparatus and are equipped with safety belts. Four of the seats in the rescue cassette are foldable so that the storage space underneath is easily accessible.
Additionally, the rescue cassette is equipped with a stainless steel stretcher holder (stretcher optional) to enable the transport of injured persons. While the standard position of the holder is horizontal, it can be tilted to facilitate the loading process.
For the air mixture management, stainless steel tubes are used which are connected to the air control system in the cabin as well as in the rescue cassette via a collective manifold. The eight breathing air cylinders (300 bar/50 l/TPED approval) are permanently installed in two dust protected compartments - four cylinders on both sides of the rescue cassette. They can be refilled via integrated refill connections on each side enabling the MRV 9000 to be connected to a standard high-pressure breathing air compressor (optional).
Several relief valves are positioned on the walls of the driver’s cab-in and the rescue cassette. They serve as outlet for excess or used air and maintain the overpressure in the rescue cassette. With the pressure reducer, the purging air flow can be adjusted to the number of persons in the driver’s cabin and cassette. To flush out harmful gases, the flush mode can be manually activated on the air management panels and silencers are used to minimise the noise. Safety bars are installed to avoid unintended manipulation of the pressure reducer.
The Dräger X-am 7000 monitors the ambient air inside the driver’s cabin and the rescue cassette for concentration of oxygen, CO2 and carbon monoxide (CO). Written instructions inside the rescue cassette give clear advice, which steps are to be taken in case the recommended thresholds are exceeded or not achieved. The X-am 7000 in the driver’s cabin and the rescue cassette are located in charging modules and are connected to the vehicle’s electrical power system.
The electrical power supply system controls the distribution of energy to all sub-systems. These include: the lighting, the gas monitors and, optionally, thermal imaging cameras or communication systems.
The cylinder pressure of the breathing air reservoirs is continuously measured and displayed inside the driver´s cabin and the rescue cassette. With this information, the available operation time of the vehicle can be accurately estimated, which significantly improves the safety of all passengers.
- Air conditioning for the driver´s cab and the rescue cassette, protecting mine rescue teams from overheating.
- External and internal communication systems allows for communication and/or data transfer between the rescue cassette, driver´s cabin and the operations centre.
- Set of four gas sensors, which can monitor CO2, CO, nitrous oxide, LEL.
- Thermal imaging cameras, one front and a rear camera, which provide a view of the area surrounding the vehicle while driving to assist the driver when visibility is limited.
- Rear view camera.
- On-board camera inside the rescue cassette.
Design and technical features
The robust and manoeuvrable vehicle was planned especially for the narrow conditions in mines. The hydrostatic drive of the MinCa’s standard model provides an optimal travelling speed combined with efficient fuel consumption especially when driving ascents. Due to the four-wheel drive and the special suspension of the axles, the MinCa always has contact with the ground, especially in uneven terrains. These characteristics allow for a maximum speed of 33 km/h and the climbing ability is up to 40%, so that every inclination in a mine can be achieved.
Depending on the regional requirements and legal standards, different types of engines are available. The basic configuration is equipped with a Deutz TCD 2012 which is a reliable water-cooled and turbo-charged diesel engine that has been on the market for 10 years. The engine is insensitive to poor fuel quality, e.g. water content. Engines with stages Tier 4 interim and final as well as EU Stage V are also avail-able.
Additionally, the frame is decoupled from the driver’s cabin and the mine rescue cassette. This, together with the torsional strength of the frame results in a high level of drive comfort for the passengers, as shocks are absorbed.
The MRV 9000 has a dual-circuit, pump-storage system as a foot brake. The axles have oil-immersed multiple disc brakes. In addition, using the hydrostatic drive as an auxiliary brake is very convenient. This effect is also helpful on inclinations. The parking brake is a Posistop or spring-applied hydraulically released (SAHR) brake, which provides additional safety.
The cabin is roll over protective structure/falling objects protection structure tested. The large, airtight doors are designed to allow easy entry with breathing protection such as the Dräger PSS BG4 Plus on the back. Driver and co-driver are seated in comfortable and adjustable seats with safety belts. Daily maintenance can be done by opening the hood, all maintenance points are easily accessible and well illuminated. If repair is necessary, the driver´s cabin can be raised hydraulically, to allow access to hydraulic components and engine.
Read the article online at: https://www.globalminingreview.com/mining/17092020/drger-and-paus-collaborate-on-mine-rescue-vehicle/