MINE SAFETY wheels are activated . The hydrostatic drive is , at the same time , an additional working brake for the vehicle – when the driver takes their foot off the accelerator , the vehicle automatically brakes . This is especially effective when driving downhill .
The vehicle ’ s electrical system works with direct current and a voltage of 24 V , supplied by two 12 V batteries with a capacity of 110 Ah each and an A / C generator ( 80 A ) with a voltage of 28 V .
Built with a width of 2.2 m , height of 2.64 m , length of 6.15 m , a wheelbase of 3.26 m and ground clearance of 260 mm , the MRV 9000 has turning radii of 3.7 m ( inner ) and 7 m ( outer ).
The vehicle is equipped with an integrated life support system to allow mine rescuers to safely reach the emergency site and evacuate injured personnel . Filtered air is injected into the driver ’ s cab and rescue cassette for breathing during the entire journey .
“ The technological basis and structure of the filling system , developed and installed by the specialists of the Dräger company , includes the following elements : compartments for storage of the cylinders with the oxygen-air mixture for breathing ; panels for controlling the supply of the air mixture ; safety valves that drain the air from the driver ’ s cab and the cassette and prevent the ingress of contaminated mine air ; gas detectors that control the condition of the air and signal the exceedance of the permissible limits of the concentration of hazardous gases in the driver ’ s cab and the cassette .”
The life support system can operate in two modes : cleaning the air and feeding the air mixture into the cassette and into the driver ’ s cab ;
The MRV 9000 Mine Rescue Vehicle has been developed to deliver rescue units safely , reliably and as close as possible to the emergency site
and flushing the cassette and the driver ’ s cab to displace contaminated air .
In the cleaning mode , used during much of the rescue operation , the air mixture from the cylinders is continuously fed through pipes into the operator ’ s cab and the cassette via flow regulators . These regulate the amount of air supply , which depends on the number of rescuers in the cab and cassette . In keeping with industry standards , some 40 litres / min per person must be supplied to remove carbon dioxide or dangerous gas mixtures exhaled via the safety valves , with used oxygen returned to the atmosphere .
The combination of the system components enables the constant maintenance of an overpressure of at least 100 Pa in the driver ’ s cab and in the cassette , as well as the prevention of methane inflows , according to PAUS . The quality control of the air , humidity in the driver ’ s cab and the cassette of the MRV 9000 are carried out with Dräger ’ s multi-channel X-am series gas detectors . After the mine rescue team leaves the vehicle , the composition and air supply are adjusted to the minimum permissible value with the help of control elements , PAUS explains .
As contaminated mine air still enters the driver ’ s cab and the cassette through the door openings after the mine rescuers have left the vehicle , the flushing mode with air supply up to 1,000 litres / min is switched on to displace the air via valves . When the gas measuring devices register the normal defined quality of the air , the mine rescuers and those being rescued can switch off their respirators .
The reserve of the breathing mixture , compressed to 300 bar and stored in six cylinders with a capacity of 50 litres each , is stored in two chambers with three cylinders each . This block with three cylinders is connected to the control units in the driver ’ s cabin and in the rescue cassette by a reducing valve , which cuts the pressure of the mixture . The pressure and air volume in the cylinder block are seen on special monitors in the driver ’ s cab . With this information , it is possible to determine the time available to the mine rescuers for the recovery operation .
The set of six air cylinders with a capacity of 50 litres each is adequate for : n Moving a unit of six mine rescuers ( two in the driver ’ s cab , four in the cassette ) to the emergency location within 60 minutes ; n Five mine rescuers performing work in the emergency zone ( one member of the unit remains in the driver ’ s cab ) for 120 minutes ; and n The return of the unit of mine rescuers with six people ( together with three injured personnel ) within 60 minutes . With such breathing capacity ( in six cylinders ), it is permissible to switch on the purging mode as follows : n In the driver ’ s cab , three times for a period of three minutes each time ; and n In the cassette , three times for a period of eight minutes each time . In this way , the mine rescue vehicle can allow the rescue team four hours of transportation in an atmosphere unsuitable for breathing .
TO SURFACE
OCTOBER 2020 | International Mining 29