The Rapid City Realty and Development Corporation (Rapid) has operations at four quarries located in Eastern Rizal.
The fleet of four PowerROC T35 rigs are achieving production of 162,000 tonnes blasted rock per month. But the highly fractured ground conditions and abrasive materials – basalt, pozzolanic and silica – make the work challenging for both operators and equipment.
The rigs, equipped with COP 1840 rock drills and T45 rods, drill for approximately five hours per day.
Working on eight-metre high benches, they drill 76mm holes at the site angle of five degrees. The drilling pattern is two meters by two meters (burden and spacing), and the hole depth is 9m, including about one metre of sub drilling.
Despite the tough conditions, Epiroc says that straight holes are the norm with only occasional deviation and each rig can drill approximately 810m per shift. The drill bits are supplied by Epiroc and have an average life of 1,750m.
Edson Lee, the coordinator at Rapid,said: "Previously, the operators were using cabinless drill rigs and that made the job very hard for them as they were exposed to direct heat and the dusty environment.
"When the PowerROC T35 came along, the first benefit the operators experienced was the air-conditioned cabins. The next was the service arrangement."
A support team consisting of two technicians – one field service technician and one service engineer – is permanently stationed in the area and keeps the equipment performing to expectations.
The team visits every rig six times a week, and each day during normal operations, they monitor the condition of the rigs according to an audit checklist.
They also perform PMS (planned maintenance) and breakdown repairs if necessary. Monthly reports are also compiled to keep the owner informed of the condition of the rigs' conditions.
The local environment is also a challenge for the service engineers as they travel from site to site, off road and in steep terrain. During the rainy season they sometimes even have to go on foot to get to where the rigs are located. Earlier, excess dust, particularly in the summer, was also a frequent problem at the sites. This was mainly due to the poor performance of the dust collectors on the previous rigs that were used, making it difficult to both operate and service the equipment. Epiroc says that, due to the efficiency of the dust collector on the PowerROC T35, this problem has been solved.