Feature: Drilling

Drilling equipment and its applications might be viewed as something of a niche activity in the construction sector. However, these machines can often be a vital link in the chain on construction projects and in aggregates extraction.
For example, repairing sections of the 1950s-era runway and taxiway at Sydney, Australia airport was a challenge for Antoun Civil Engineering for a number of reasons. The airport handles 300,000 aircraft movements and 37 million travellers per day, and although the repairs were urgent, replacement of the damaged slab areas could only be carried out during the normal runway shutdown period of 11.00 pm – 4.30 am each night. Of course, should the runway be unable to reopen on time, Antoun Civil Engineering would face massive penalties.
Efficient equipment was key to working around this time constrain on the cycle of demolition, removal, pouring and achieving structural strength before the airport runway reopened each morning.
Two key machines were two dowel pin drills from Minnich Manufacturing, an A-1C-48, and an A-2C-48, equipped with an optional dust collection system. They were used for drilling the 36 mm diameter holes in the existing slabs for dowel bars to be inserted before pouring the fresh concrete.
The recommendation that Minnich drills would be the right tool for the job came down from the management team at distributor Volumetric, which has worked with Minnich Manufacturing for some five years. This was founded on impressive service and support from the Minnich Manufacturing sales team which has seen the relationship blossom to a point where Volumetric is the exclusive Minnich equipment distributor for all of Australia.
“We were able to drill the holes that we needed in existing slabs in about 45 seconds per hole for the single drill unit, and two holes in the same amount of time for the double-gang unit. Not only were the Minnich drills efficient, but safety also came into play for us – we really didn’t want our guys down on the ground manually drilling the dowel-pin holes,” said Robert Antoun, of Antoun Civil Engineering.
Each slab being replaced required 45 holes, so this potentially lengthy process was cut to about 35 minutes with the single-gang drill and 20 minutes with the double-gang unit. Another plus point was that each drill only required one person to operate it. After two and a half weeks of an aggressive schedule, working six nights a week, Antoun Civil Engineering completed the project ahead of time and under budget.
Stabilisation
Robit is pioneering a ground stabilisation system that uses fibreglass grout-injection tubes instead of steel ones, having acquired the patent for the system in 2014. The idea is that these form an easily-demolished temporary structure, so they are suitable for reinforcing tunnel faces in between phases of excavation.
The drilling for the reinforcement work can be carried out either with surface rigs or in tunnels with jumbos and the grout injection also uses standard equipment.
The company has supplied the system to the A.T.S. Infratunnel rail project in Switzerland where there was a risk of a face collapses. The roof was being supported with traditionally grouted steel tubes (forepolling), but 76 mm diameter fibreglass tubes were drilled up to 21 m into the face to reinforce it ahead of excavation. This meant the tunnel could advance up to 12 m, with 8 – 9 m of fibreglass tubes still supporting the face before new 15 m steel tubes had to be drilled and grouted into the roof.
Robit said the method proved a better solution than self-drilling anchors, which had been unreliable on the project and hard to demolish as the tunnel progressed. It added that its solution also met the project’s requirement for hole straightness, which the anchors did not.
New equipment
New from Atlas Copco is Bench Remote, an operator station that acts as a full remote control for up to three surface drilling rigs simultaneously.
The unit was designed to reduce the risk of working close to unstable and hazardous benches or close to unstable faces. The Bench Remote operator station can be used up to 100 m away from the drilling area and up to 30 m above the rig, as long as there is a direct line of sight with the drill rig doing the work.
And it is not only a question of safety. Atlas Copco product manager Mattias Hjerpe said, “The Bench Remote can handle up to three SmartROC D65 rigs in parallel. This multiplies the operator efficiency and was made possible by the full drill cycle automation.”
The Bench Remote can be installed in a vehicle, trailer or container and all controls and screens are the same as in the real cabin on the rig. Communication, including machine control and safety functions, takes place over a closed WiFi network. This makes it independent of local network infrastructure. If the network is lost due to distance to the drill rig, it will shut down for safety reasons.
Atlas Copco said all its SmartROC D65 drill rigs can be upgraded for Bench Remote operation.
A specialist area like drilling is never really awash with new machines being launched, but last November’s Bauma China exhibition saw some interesting new products unveiled.
Atlas Copco launched its PowerROC T50 drill rig at the show, which was designed and is manufactured at the company’s Nanjing, China plant.
The company said the aim when developing this machine for quarrying and open pit mines was to develop a robust, powerful, fuel-efficient rig that could deliver performance in an easy-to-use, straightforward design. Key features include a new type of extendable boom, a powerful hydraulic COP 3060 rock drill, and a choice of Tier 3 or Tier 4 engines.
The new boom has been designed for quick and easy positioning and the company said the high feed force helps ensure straight holes. Other features include a straightforward hydraulic and electrical system for easy operation, push-button controls, a ROPS/FOPS certified cabin with large windows and extra vibration dampers, and good ground clearance for easy tramming in rough terrain.
Product manager York Yang said, “The PowerROC T50 is an important milestone for Atlas Copco in Nanjing but mostly for our customers around the world. We know that this product is very much in demand for the customers who desire the straightforward as well as powerful drill rigs.”
One of the first rigs to be made went out on trial with Eire Contractors of Durban, South Africa. John Moffat, founder and CEO of Eire Contractors was impressed. “The rig’s power, speed and fuel efficiency meet our objectives for achieving maximum productivity with minimum input. In addition to substantial savings on diesel, the rig drilled the holes with ease. A comfortable operator is a safe and productive operator so the fact that the rig offers the same operator comfort levels as the previous model is very important to us,” he said.
Sandvik also used the Bauma China exhibition to unveil new rigs to a global audience in the shape of the new Tiger surface drills. Designed for applications such as road cutting, pipeline drilling and foundation drilling, as well as production drilling in medium-sized quarries, the machines are said to offer power, strength and performance.
Features include a low centre of gravity and heavy-duty tracks, while the fixed boom has a rod handling system, and Sandvik’s proven rock drills.
In the cab there is a tailor-made user interface, which allows all drilling functions to be handled with a single joystick control, with all drilling parameters being easy to adjust. The series consists of two models, the Tiger DG700 for 64 – 115 mm diameter holes and Tiger DG800 for hole sizes of 64 – 127 mm.
Demolition robot maker Brokk and drilling equipment manufacturer TEI Rock Drills have developed the TE160 hydraulic drifter attachment for Brokk 100 or Brokk 160 remote controlled machines.
“Heavy jackleg drills are difficult to move and can quickly wear out the operator. With the Brokk machine and this drill head, they won’t tire so easily,” said Peter Bigwood, vice president of sales and marketing at Brokk. “Instead, they can run powerful drilling equipment in tunnels, mines and demolition sites for longer and from safe distances.”
The Brokk 100 is only 45 inches (1.14 m) tall and 31 inches (0.79 m) wide with the stabilisers folder in, so can be used in confined spaces and is narrow enough to fit through doorways or onto elevators.
At just under 26 inches (0.66 m) long, the TE160 is the smallest drill attachment from TEI, but still delivers 35 to 60 foot-pounds (47 – 81 Nm) of impact energy at 5,000 to 6,500 blows per minute.
Another important feature is that Brokk has integrated the rock drill’s controls into the robot’s. “Operators can control the Brokk and the TEI drill with a single control rather than one for the machine and one for the attachment,” Mr Bigwood said. “This makes the Brokk and drill combination more convenient and practical, and also frees up an extra worker who normally would be required to operate the second control.”
Meanwhile Rockmore International has launched its T series down-the-hole (DTH) hammer line, the first model being the ROK 600T. The new T series uses drill bits with standard shank connections that no longer require plastic parts commonly known as Blow Tubes or Foot Valves. Rockmore said the elimination of this part offers technical and economical advantages, with better reliability without any compromise on performance.
The company said that although such “Tubeless” DTH hammers have been offered before, drilling performance was often compromised when designed to operate with an industry standard bit shank. Such products have also often used bits with a proprietary design, which limits their availability.
Pejman Eghdami, executive vice president of Rockmore International said, “With our emerging T class DTH hammers, we are offering the drilling community a balanced solution of improved reliability without compromising any drilling performance. Impressively, we have achieved this by incorporating standard industry shank connections into the overall design concept.”
The ROK 600T is a 6-inch (152 mm) rated for drilling
6.1-inch to 7.0-inch (155 to 178mm) diameter holes. It is also suitable for water well drilling. It accepts the industry-established QL60 bit shank model, but with the Blow Tube/Foot Valve removed. The corresponding bit connection for this hammer is designated by Rockmore as QL6T, which has an identical shank design to the QL60.
Meanwhile, Doosan has expanded its compressor offering in the Middle East and Africa and can now supply units from 185 to 1500 cfm (5.0 to 42.5 m3/min) at output pressures from 7 to 35 bar. The range includes models with engines compliant to Tier 1, 2 and 3 exhaust emissions regulations, so machines can be chosen to suit different countries’ regulatory frameworks and the fuel quality levels available.
For quarrying, deep drilling for oil and gas exploration, water well drilling and pipeline work, as well as foundation drilling in general construction, Doosan offers a number of different models, such as the XHP900WCAT-T1 and XHP1070WCAT-T1 models. These have free air deliveries of 900 cfm (25.4 m³/min) and 1070 cfm (30.3 m³/min), respectively, at an output pressure of 24.1 bar.