MINING VEHICLE WASH DOWN
STEAM, SAFETY AND STERILISATION Let’s not beat around the bush. Mining is a lucrative industry so there’s no shortage of suppliers queuing to get their foot in the door, particularly when it comes to industrial pressure washers. Does higher cost equal better quality, or are there other factors to be considered?
In this day and age, a driving factor for mines is Health and Safety. There are OH&S policies for almost any situation, so what safety considerations come into play with pressure cleaners and what features do they require in order to make them compliant?
Well, that’s big question requiring an expert answer, so the AMR spoke to Steve Molson from trusted mine site provider, Minespec Hire, to rinse out the truth when it comes to pressure washer safety.
So, what are the key criteria for an OH&S compliant pressure cleaner?
ZERO-PRESSURE BY-PASS SYSTEM There is a pressure activated valve in the water outlet side of the pump, which engages as soon as the trigger is released by the operator. The pressure spike causes the by-pass valve to open, recirculating water back through the pump and dropping the pressure at the lance to zero. With this feature, even if the lance was to be accidentally removed whilst the pump was still running, there is no water pressure in the line, rendering it perfectly safe.
To be fully compliant, this by-pass valve must also be locked, so that the open line pressure always remains zero. An added safety benefit of this system is that when the operator pulls the trigger to start washing again, the bypass valve gives a soft-start as pressure gradually builds.
This eliminates sudden and unexpected kick-back from the gun, which has caused many injuries to date.
SPECIALISED ‘DISCONNECT’ HOSE FITTINGS
Conventional, pull-back, quick-release fittings (similar to those used in air lines) can be accidentally disconnected with dramatic results. Imagine a 2m lance, cleaning a machine with 5000psi discharging from the nozzle. Picture that lance suddenly popping free of the coupling and being propelled forward like a spear with all that pressure behind it.
Picture also the non-bypassed flexible hose end now thrashing around with enough water pressure to remove fingers and crack bones with the metal coupling.
This may sound dramatic, but these accidents have and do happen. To help mitigate this risk, pressure washers should be fitted with special disconnect fittings that must be twisted several full turns to separate the hose from the lance.
FIXED THERMOSTAT FOR HOT WASH Hot pressure washers not only make short work of large quantities of grease, dirt and oil, they are also excellent tools for sterilisation of areas such as toilets, showers, kitchens, laundries and other areas where virus transmission is at a higher risk on a mine site.
Typically, these machines use a diesel burner to heat the water that can reach 100ºC at full flow, regulated by a variable thermostat. Some can be dialed back to actually clean with steam.
Problems can occur in hot washers if the trigger valve is damaged and the water is allowed to drizzle out, instead of being stopped completely. By dribbling out, the diesel burner still senses water flow through the system and stays on.
The problem here is that there is too little water flow to bleed off the mounting pressure – despite the thermostat - and the end result can be a catastrophic explosion.
This is why a fixed thermostat, set to a maximum of 87ºC, will add another layer of safety. If pressure builds in the burner, a manual dump valve opens, allowing cool water to flow in, expelling the hot water and pressurised steam, thus eliminating the risk of a ruptured burner.
This device is located inside the exhaust pipe and prevents glowing, red-hot carbon embers from being shot out of the pipe and potentially starting fires. In the tinder dry heat of the Goldfields, with fuel floating on water or in workshops strewn with oily rags, spark arrestors are a must.
At Minespec Hire, all trailer-mounted pressure cleaners are fitted with Australian-made, mine-specific safety features to ensure that your team and your equipment are safe.
This experienced WA company also offer hire options ranging from one week to 12-months, and in addition to mobile pressure cleaners, have a wide range of equipment and underground vehicles for hire. All vehicles have been fully workshop inspected and tested, ensuring maintenance is up to date and the vehicles are in perfect condition.
Considering the high cost of outright purchase for mine equipment and underground vehicles, Minespec offers a cheaper alternative with the option of maintenance and support via their base in the Goldfields. They offer a completely unique service to the mining community.
As mentioned, Minespec have an established mechanical repair and maintenance workshop in Kalgoorlie. Their hire vehicles are available from this branch and vehicles can be returned to the workshop for major repairs and servicing. On-site servicing and repairs of vehicles and 24-hour breakdown service is also available to keep critical mine vehicles in operation around the clock.