Job versatility, boring accuracy and operator ease are high on the list of new features

The industry’s major underground drill suppliers have provided a steady flow of product announcements and introductions for underground production applications over the past year, ranging from performance, control and safety enhancements on high-output tophammer rigs, to quieter, more efficient and user-friendly designs for jackleg-mounted drills, and completely new models for special purposes. Here’s a quick rundown of the highlights:

1 Sandvik DL431 TH ri252822
Sandvik Mining’s upgraded DL431-series rigs are now equipped with a zoom sensor that ensures fast, accurate positioning of the boom for increased accuracy and reduced ore dilution.

Sandvik Upgrades Tophammer Line
During the second half of 2013 Sandvik Mining announced a significant performance upgrade to its DL401-series underground top hammer production drills—an effort that the company said is intended to ensure continued and high drilling productivity, rock tool performance and process optimization in a wide range of mine conditions. The upgrade covers Sandvik DL411-, DL421- and DL431-series longhole drills and enhances performance in several areas:

  • Accurate feed pressure control and feed controlled by rotation (torque drilling)—resulting in better sensing of hole conditions, energy transfer, penetration rate, rock tool service life and drilling accuracy, especially in soft rocks and downhole drilling,
  • Zoom sensor system on DL431-series drills—ensuring accurate and fast positioning of boom to pivot point in fan drilling, increased drilling accuracy and reduced ore dilution,
  • Use of Power Extractor for uncoupling rods in automated drilling—easier and faster opening of joints reduces nondrilling time, increases drilling capacity and rock tool service life and reduces rock drill maintenance cost,
  • Automatic flushing sequences in drilling cycles at preset intervals—ensuring improved hole stability, minimized interruptions, higher drilling capacity and improved rock tool service life,
  • Independent percussion pressure control between drilling and backhammering—enabling optimization of pressure levels for each function separately, for maximum penetration rates, easy uncoupling of rods and improved tool service life, and
  • Automated rock drill stabilizer pressure control—automated pressure adjustment releases operator from manual work during fan drilling and improves operator performance (available with HL1560T rock drill on DL411/DL421).

The upgrade became available on new DL401-series drills in January 2014, along with aftermarket kits for units already in the field.

Jukka Naapuri, product manager for underground tophammer production drills, said the automation and intelligence introduced in DL401-series production drills will help Sandvik’s customers achieve more consistent longhole drilling productivity in a wide range of mine conditions.

“At the same time, we have taken the opportunity to introduce a number of features designed to minimize interruptions and delays in the drilling process, reducing non-productive time, helping deliver more meters of rock drilled per shift and to improve tool economy further,” Naapuri said. “In addition, the ability to achieve more accurate fan drilling with the new zoom sensor system on the DL431 means improved ore recovery, reduced dilution and fewer oversized boulders in the stopes to be processed.”

Naapuri said that the performance of DL401-series drills had also been optimized for automated and tele-remote drilling, allowing full-fan remote operation of one or more machines to be carried out by a single operator.

Sandvik’s DL401-series drills are electrohydraulic longhole rigs designed for large-scale underground mining in 4 x 4-m or larger cross-sections. The drills are mounted on 4-wheel drive, frame-steered and diesel-powered undercarriages and equipped with Sandvik HL710 or HL1560T hydraulic rock drills, drilling modules, longhole booms and FOPS/ROPS certified operator stations. According to the company, the 360-degree boom rotation and wide swing/tilt angles make the units suitable for longhole drilling in most mining methods and various drilling applications.

Onboard CAN-based technology allows the operator to set the rig for any rock conditions, and enables easy upgrades to various levels of automation. Drilling and tramming is carried out from the ROPS/FOPS-certified operator's platform, while drilling from a remote position next to the machine is also available.

Sandvik also introduced the new DD211 underground hard rock mining development drill for narrow-vein applications. A single-boom electro-hydraulic drill rig, the DD211 is designed for development drilling, specifically in tight tunnels and curves.

According to Johannes Välivaara, product manager, underground development drills at Sandvik Mining, the DD211 was developed primarily for Latin America, North America and CIS markets and has the same key safety and productivity features as the rest of the company’s range of drill rigs.

“A major feature of this new rig is [its] electro-hydraulic controls, designed to enable accurate drilling performance in a wide range of rock conditions, ensuring efficient control across a variety of operations,” Välivaara said. “Drilling power is provided through our proven RD314 rock drill, ensuring not only improved drilling performance and precision, but also reduced drill steel consumption.”

Välivaara said the DD211’s standard configuration includes a Sandvik SB20 boom, providing maximum coverage up to 26 sq m. Optionally, it can be fitted with the new Sandvik SB20NV boom, incorporating a CFX 6/12 telescopic feed, and designed for applications where high levels of maneuverability are required when drilling upholes and cross-cuts in narrow space environments. Drilling is controlled through the THC561 electro-hydraulic system, incorporating constant speed drilling controls, stop-and-return automatics and air-mist flushing with rock drill return.

Välivaara said oerator comfort has been improved through the use of a more ergonomically designed seat, including the ability to turn the seat for drilling, and low-effort joystick controls.

The Acid Test
In January, Sandvik said it would soon become the industry’s first supplier to offer fully ROPS-compliant, acid-proof cabins for underground drilling. The cabins will be available on the company’s forthcoming range of Next Generation underground rigs, starting with Sandvik DD422i development drill, which is due for release in mid-2014.

“Acid-proof cabins on our underground drill rigs have been FOPS-compliant since 2005, but ROPS certification is an important complement to the existing standard safety features on all our Next Generation drill rigs,” said Jan Petzold, director of underground drilling at Sandvik Mining.

Sandvik pointed out that many underground mines around the world have highly corrosive conditions, requiring the use of stainless steel for component—including cabins—in order to protect machines against rust and corrosion. Stainless steel used in the construction of acid-proof cabins has not previously been able to satisfy the strength requirements for ROPS compliance.

Sandvik said recent independent accredited testing by Finland’s MTT Vakola, Measurement and Standardization, confirmed the acid-proof cabins on its Next Generation underground drill rigs are now fully compliant with both EN ISO 3471 (ROPS) and EN ISO 3449 (FOPS).

“We’re now the only equipment supplier in the world offering FOPS/ROPS-certified acid-proof cabins for drill rigs up to 35 tons,” Petzold said.

New Atlas Copco Production Models…
In 2013, Atlas Copco announced the launch of five new underground drilling products at the bauma trade show. The company said its new Boomer E-series rigs for underground face drilling will feature the powerful COP 4038 series rock drill or the new COP 1800+ series drill. The E-series would also include a new Rig Control System and an updated version of Atlas Copco’s advanced Underground Manager System with improved user interface. Also introduced at bauma was a Dry Drilling System for water-free face drilling.

Atlas Copco’s COP 4038 high-frequency rock drill is said to be 20%–30% faster than the nearest contender, and has been optimized for hard rock conditions. The drill is designed for 43- to 64-mm drifter holes, using Atlas Copco’s double damping system to absorb reflex shock waves, making it possible to drill exceptionally fast without increasing wear on the drill steel, according to the company.

In introducing the COP 1800+ series drills, the company said the new unit provides the same performance as the previous standard COP 1800-series, but expands recommended service intervals by 50%.

The latest Boomer E series rigs feature an upgraded control system with a user-friendly interface, a larger intuitive-touch screen, two multi-functional joysticks instead of four, and Atlas Copco’s Underground Manager rig support planning software. During system development, Atlas Copco said it focused on creating an intuitive and easy-to-use operator system. All functions have been grouped in nine blocks under a new tree structure for easy navigation within the system. Together with the new touch screen display, operation is streamlined and training time is reduced for new operators.

The rig control system’s two new multifunctional joysticks carry primary functions for drilling grouped at the top of the joystick, allowing the operator to focus on drilling instead of searching for functions.

The bauma introductions also marked the availability of a three-boom jumbo that can operate completely water-free. The dry drilling system available on the Boomer XE3 C uses compressed air to keep the hole free from cuttings and a suction nozzle around the drill string to eliminate dust. The suction hose then returns the dust to a filter unit and a sealed container for simple dust logistics. The dry drilling system is intended for sites where water is scarce or where it’s not possible to use water due to rock conditions or surrounding temperatures.

3 Atlas Copco Easer
Atlas Copco’s new ‘Easer’ mobile raise boring rig is designed to set up much faster than conventional raise boring machines. It will produce opening holes up to 750-mm diameter and 60 m deep.

…and a Mobile Raise Borer
Late in 2013, Atlas Copco announced the forthcoming launch of a new mobile rig for boring ‘opening holes’ in mines. The new Easer rig can perform both boxhole boring and down-reaming.

In explaining the background of the rig’s development, Atlas Copco pointed out that raise boring has been considered as the safest and most productive way of driving raises in most mining applications. In block caving, and in most types of sublevel mining, a large number of short raises act as openings for rock to expand into when blasting. Traditional raise boring machines typically require a concrete platform and tie-down bolts to keep the machine stable during operation. In the total turnover time for short raise boring, for example, actual boring time is often below 50%.

The rig is designed to produce opening holes with a maximum diameter of 750 mm and a hole depth of up to 60 m. It uses standard 200-mm (8-in.) boring rods with a 228-mm (9-in.) pilot drill bit.

“Our mission in developing the Easer has been to speed up the operation,” said Johnny Lyly, product manager. “The timeframe for drilling a 40-meter opening hole, from setup to take down, is less than 30 hours, and set up/take down is done in less than one hour.” All necessary operating equipment is integrated into the carrier with the exception of the rods, and setup does not require site preparation.

The Easer, said the company, offers drilling modes identical to traditional raise boring rigs: box hole boring, down-reaming and conventional raise boring. To switch from box hole boring to down-reaming, the gearbox is rotated 180°, a simple operation that can be carried out in an underground workshop.

Atlas Copco said the name ‘Easer’ comes from the expression “ease off,” meaning to release pressure, used in reference to the blasthole into which rock expands during blasting.

The Easer rig is scheduled for launch during 2014.

4 Boart S250
Boart-Longyear’s S250-M3 pneumatic drill.

Boart Longyear’s Quieter Pneumatic Rig
Boart Longyear has developed a soon-to-be-introduced replacement for its popular S250 handheld pneumatic rock drill. The S250 has been offered in in three primary configurations—jackleg, stoper, and sinker—and its newest version, the S250-M3—will continue that lineup, according to the company, but with the addition of new technology that produces 50% (6 dBA) less sound pressure than the leading competitor rock drills; experiences less wear due to the reduced amount of energy transferred into the components of the drill; and provides 39% more torque and better penetration (more than 6 in/minute at 110 psi.

The -M3 will be offered with both 22- and 25-mm hex chuck ends to accommodate popular steel sizes. The jackleg version will weigh approximately 96 lb (43.5 kg), with the standard airleg weighing 34 lb (15.5 kg). The sinker version will weigh in at 84 lb (38 kg). Other preliminary specifications include a bore of 3.126 in. (79.4 mm), stroke of 2.884 in. (73.25 mm) and 2,200 blows per minute at 90 psi (6.2 bar).

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