Curragh Mine is located in the coal-rich Bowen Basin of Central Queensland and it covers an area of approximately 12,600 hectares. It is situated 14km north-west of Blackwater and approximately 200km west of Rockhampton.
The mine predominantly produces three products. These include low ash hard coking coal, pulverised coal injection coal and high ash steaming coal. It supplies both the domestic market and markets worldwide. Paramount to the mine’s efficient operation is the health and safety of all employees.
The mine constantly reviews its procedures and equipment to ensure the safety of staff, and as part of this process the mine’s maintenance team trialled the new Kemppi Minarc Evo 140 VRD (voltage reduction device).
"You can no longer use a welding machine on a mine site without VRD and a lot of our existing welding equipment was getting on, so we were keen to have a look at some of the new welding equipment," explained Ron Kemp of the mine’s maintenance team for area mobile equipment.
The maintenance team for area mobile equipment is responsible for ensuring that all mobile mining equipment remains in operational condition to meet mining requirements. It maintains the mine’s rear dump trucks, loading units, dozers, graders and all ancillary equipment. The team consists of 15 men per shift who are mainly boilermakers with extensive welding experience. Over the years they have used various welding packages.
"We were already familiar with the Kemppi brand having used their welders in the past and we were keen to trail the new VRD model. We were after a welding model which not only met all the safety criteria but was light to carry and very portable.
"The machine would be primarily used to weld low hydrogen electrodes. Apart from general field welding we always need to fix handrails to our heavy mobile equipment and we wanted a dedicated machine for this task," explained Ron. Contacted by his local Kemppi dealer, Ron raised the prospect of trialling the new Kemppi Minarc Evo 140 VRD machine to which the dealer readily agreed.
The Minarc Evo 140 VRD model is designed specifically for the Australian mining environment. Fully portable, the unit is perfect for repair and maintenance applications around the mine site. It is equipped with a range of safety features as standard. Its integrated VRD has been tested to meet local standards and mine site recommendations of achieving lower than 35V open circuit within the required 300ms from peak load.
In addition, the Minarc Evo 140 features a VRD operational status light and ‘fail to safe’ function in the event of VRD failure. It also has an electrical supply current (100% EDI 1eff ) of 10amps and is protected by an IP23S environmental rating. The device meets Australian standard AS60974-1 and Mine Safety Standard MDG25.
Compliant with safety regulations, the Minarc Evo 140 delivers safer welding in category A, B and C environments. Suitable for MMA and TIG processes, the unit is energy efficient and boasts large voltage reserves and automatic arc force control.
After trialing the Minarc Evo 140 VRD for three weeks Ron bought two 140 VRD units for his team. "I think it’s fair to say we were all suitably impressed. Apart from having all the safety features, the machine only weighs about 5kg so it is very light to carry around. This is always a plus when you have to climb up on a dozer or dump truck to weld something. And because it’s so light and portable you can also easily carry a few rods and a 240 lead with you,"
The team also found the device easy to use. "With the Kemppi 140 VRD you can strike a rod, stop and clean up, and then restart quickly and easily. Or you can stop, change your position and restart without any hassles, so you don’t find yourself wasting time. It helps you get the job done quickly," said Ron.
"We also liked the 140 VRD’s large, user- friendly, digital meter display. This is a bonus because it’s so easy to read. Many other models only have dials to adjust and no readout. For us, the Kemppi Minarc Evo 140 VRD has been the perfect choice. It’s comfortable to carry around, very easy to use and you get a quality weld."