Atlas Copco has developed a powerful, robust and compact hand-held hydraulic rock drill that sets a new global benchmark in efficient and safe low reef rock drilling.
Weighing only 45 kg, the 7.9kW, 525V Power Pack drives the HRD100 rock drill which is capable of drilling 700 mm in hard rock in only one minute using a 36 mm diameter drill bit. “The Atlas Copco HRD100 is a first-of-its-kind and one of the most powerful drills in the industry,” confirms Neville Stewart, Atlas Copco Business Line Manager – Construction Tools Division.
Stewart explains that, in answer to the mining industry’s drilling equipment requirements, the objective was to produce a powerful, efficient, compact rock drill for easy maneuverability and operation in stringent underground conditions where heat, low profiles and steep difficult-to-reach areas are the order of the day.
“To achieve a compact and light weight design, we had to bring these units down in size but, most importantly, without compromising on performance. It was a challenge technically because nothing similar was available anywhere in the world and we had to design our own motor from scratch.
The HRD100 has been specially designed and engineered to offer industry-leading features in terms of efficient, reliable performance, operator safety and comfort, low maintenance as well as environmental considerations. The result is a complete package, consisting of the RD100 rock drill, a unique power pack and a selection of pusher legs with an incredible power-to-weight ratio that meets the mining industry’s requirements spot on. “In other words,” states Stewart, “all the fundamental requirements that mines demand of equipment to ensure maximised uptime and optimum production levels.”
“It all comes down to drill speed because this is what ultimately determines productivity,” stresses Stewart. “The HRD100 delivers between 10 to 25 Nm torque and runs at an impressive 37% efficiency at the drill steel. The combination of high drill rates and low operational costs per metre drilled makes the rock drill considerably more energy efficient compared to conventional pneumatic or electric rock drills. “There will always be losses but the secret is to minimise these losses and built-in features such as idle mode and power-on-demand do exactly this.”
The rock drill’s four actions ensure successful drilling: Percussive Impact breaks the rock by hammering impacts from the rock drill to the drill bit at the bottom of the hole; Feed Force keeps the drill bit close in contact with the rock. Rotation which is adjustable 150 to 200 rpm, moves the drill bit to a new position to make the next blow as effective as possible and Flushing with a high output technology removes drill cuttings to allow for continuous drilling.
The flexible unit features a built-in exchangeable valve that optimises drill rates at different rock conditions to enable the unit to drill into virtually any rock condition from soft rock (100MPa typically found in South African platinum mines) to hard rock (250MPa common in local gold mines). Furthermore, the HRD100 can drill both horizontally and vertically while the adjustable rotation saves energy and allows for easier drilling. The stackable power pack monitors all vital functions and thus compensates for pressure changes automatically.
A robust frame design, complete with shock absorbers, protects all functional parts of the unit. The rock drill is capable of efficient operation in ambient temperatures ranging between +5°C to +40°C. The Smart function evaluates oil flow and temperature enabling the water-cooled power pack to work without power loss or overheating for optimised reliability.
The compensator makes it possible to transport the power pack at any angle, even upside down and it can operate at up to a 45 degree angle.
The objective is to keep the rock drill underground for as long as possible and reliability and low, easy maintenance make the rock drill virtually maintenance free. Operators can replace the chuck underground and service which is only required after 500m of drilling, is quick and easy. The accumulator is maintenance free requiring it to be charged with inert nitrogen gas during services only.
The HRD100 takes operator comfort and safety to a whole new level. The light weight unit (weighing only 23 kg without tail hoses and 25.8 kg with 1.2 m tail hoses) can be operated with one hand. Measured noise levels were reduced by 10 db(A) which is a 50% reduction to achieve sound power of only 111db(A) while sound pressure (at the ear of the operator) is a mere 102 db(A). The addition of the soft-start function as well as the polyurethane cover shields not only ensure quieter operation but also make the rock drill shockproof. Added safety features include a torque limiter, an emergency stop, power on demand and a reduction in motor rpm in idle mode. The automatic standby mode, over-current protection, covered exposed parts and an auto disconnection of the supply of electricity, allows for protection against electrical shock.
The pusher legs, available in four models from 0.7 – 1.5m, are powered by water with a single point stainless steel connection to the rock drill. The water is used as both a coolant as well as a dust suppressant. Water consumption is a mere 12 l/min.
“The fact that there is no oil exhausted from the drill is one of the main advantages of hydraulic operation,” says Stewart. “The little oil that is used in the drill is 100% biodegradable and the power pack switches off if pressure loss is detected to reduce risk of oil spillage.”