Balancing actMarch 7th, 2012 | Posted by in T4W
For the Serra family, having a versatile drill rig is necessary for the region and the type of work they do. The multi-generation family business is located on the fertile Atherton Tablelands of northern Queensland, Australia, and the T4W is its work horse, drilling bore holes for agriculture, residential and mining customers.
Before his family started the business in the late 1960s, Joe Serra said if you needed a well drilled, you’d put your name on a list with a drilling company that would come around occasionally. Joe’s father saw a business opportunity. He was right.
Joe admits that when his father started also doing work for the business he bought the wrong rig. It was a mud rotary rig that didn’t work in the varying formations of the Tablelands.
In 1981 they bought their first used T4W and that gave them the hard rock power they needed, and they’ve stuck with the T4W ever since.
After 30 years of running T4Ws the family recently purchased its newest rig. “The old rig was running great, but with the incentives offered by the government it didn’t make sense not to buy now,” said Joe. The Australian government offered tax incentives to make capital expenditures at the time.
Today the family business drills water wells for irrigation and drinking water while also doing work for mines in the region. Joe likes the versatility of the T4W that allows him the finesse to drill 620 feet (190 meter) water wells—including running 118 feet (36 meters) of slotted PVC casing at the bottom—yet the strength to drill 950 feet (290 meters) of steel casing in the coal mine region.
The distance the family drilling business will travel has grown over the years. Population and farming development has leveled off. So,Australia’s mining industry has developed into a good base for the Serra business. Within a day’s drive coal fields and metals mines offer an alternative source of revenue drilling for ground monitoring, de-watering and chip sampling.
In the Tablelands near the family farm where the Serra family got its start, the ground is rich with volcanic surface soils that make the region perfect for everything from bananas to potatoes. The land was once a tropical jungle that was cleared in the first half of the last century. Below the surface is honeycombed basalt rock that holds a large amount of water. Below that is solid granite.
Joe gives an example of the formation: 2 feet (0.6 meters) of surface soils, 20 feet (6 meters) of sub-soils, 200 feet (61 meters) of clays, 80 to 90 feet (27 meters) of decomposed or 50 to 60 feet (18 meters) of honeycombed igneous rock.
“When going through the decomposed formation, it’s important to slow down,” Joe cautioned. Although it’s fast drilling, the ground can swell behind the hammer causing it to become trapped below the expanded ground. Joe said going slow allows the formation to move with the hammer and not swell after penetrating the formation.
At times they also encounter sandstone below the volcanic rock, but once the tight granite is reached, there will be a low water yield.
The hammer that works best for the family business is Atlas Copco Secoroc’s COP 64 Gold. In the past Joe went with another brand, but he said it couldn’t hold up. In the toughest blasthole drilling situations. Joe said he can get 25,000 hours on a hammer.
Joe talks about one situation that other drillers might encounter. On a mine property he said they were getting half the life out of the hammer. After looking at all possibilities, he said it came down to the water they were injecting. The minerals in the water were caustic, reducing the piston life. The solution was to bring water from off-site to fill the tank.
After so long on the job, troubleshooting has become second nature to Joe and the rest of the family, similar to most drillers. Unlike some, however, the Serra family has been at it for three generations.