From the largest rotary electric and diesel models to highly mobile crawler top hammer and DTH track drills, surface mines of all types and sizes have access to a wider range of technology options, reports Paul Moore.
Rotary rig developments
Joy Global has added to its diesel rotary blasthole drill product offering to provide a wider range of solutions for hard rock applications. The new P&H 285XPC provides up to 53,524 kg of bit loading specifically designed for 270 and 311 mm diameter holes, making it well suited for the majority of copper and iron applications. “This new drill will carry on the P&H legacy for durability,” stated Eric Wilkinson, Product Manager. “It will feature the same powerful propel structures and robust pulldown systems as our other P&H drills.” The new drill also features the Universal Drill Cab (UDC) utilized on other P&H drills. This commonality of controls will allow experienced operators to quickly and easily transition to a P&H 285XPC. The UDC provides the operator with a clear, unobstructed view of the drilling area and the surrounding environment. Its expansive windows and video cameras provide the best visibility in the industry and ensure that the operator is able to maintain complete situational awareness while drilling and propelling. Additionally, the FOPS Level II certified structure combined with shatter-resistant glass protects the operator from harsh mining conditions.
Caterpillar’s rotary drills, based on the former Bucyrus range (SKS, SKF, SKFX, SKL, 49HR, 59HR) now include a new B Series model, which is just now starting to be manufactured commercially. The new MD6420B (former SKS) has a bit load force of 42,000 kg and three different mast lengths to choose from. It can drill holes as large as 311 mm in diameter and as deep as 74.4 m making it ideal for high-production drilling in hard or soft-rock applications. The rotary drill features “heavy-duty structures, rugged components, a comfortable cab, convenient service access and many other attributes that reduce cycle time, improve productivity and lower ownership costs. “ As the next generation of the MD6420, the new MD6420B includes numerous new features and systems such as a new Cat 345 undercarriage with GLT, a choice of three powertrain configurations, choice of both rotary and DTH drilling methods and three mast height choices of 10 m, 13 m, or 16 m as well as a new hydraulically operated bit basket; and a heating and air conditioning system roof-mounted for efficiency. It has reduced vibration and sound levels, now down to 77 dB(A) and an advanced drill controls system for easier operation and operator comfort. It also has a new diagnostics system with a touch screen monitor; and the option to use the Terrain for Drilling system. Lastly it has fewer hydraulic components and hoses with improved hard pipe routing; as well as a cascading and self-levelling staircase that improves entry and exit from the deck.
One of the largest rotary drills in the range, the MD6640 (former 49HR), has a new Cat undercarriage and Cat components. The new Cat 390 excavator style undercarriage now comes as standard and has addressed issues such as tramming limitations, turnability and track tensioning. The mainframe structural design has benefitted from 15,000 hours of finite element analysis and 4,000 hours of strain gauge testing to evaluate the structural integrity of the mainframe, side frames and mast. The use of square tubular members in the mast also has a distinct advantage in strength-to-weight ratios over angle iron. Comparing size-for- size at the same weight per metre, square tubular members have twice the bending strength of angle iron and have a definite advantage in their resistance to buckling. The rack and pinion system provides constant pressure at the drill bit. Bucyrus was the first to pioneer the rack and pinion design in 1952 and this has been further refined on the MD6640. The design of Caterpillar’s mast machinery integrates the pulldown and rotary drive into one system, eliminating the higher maintenance associated with chain or cable systems. Introduced as the 49HR in 1986, the now MD6640 remains ahead as a market-leading and highly productive machine that drills holes from 244 mm to 406 mm diameter. It can also angle hole drill to 25° and has a maximum bit load of 63,975 kg and a maximum working weight of 154,224 kg.
Antofagasta Minerals’ Los Pelambres is one of the largest copper mines in the world, and recently chose Atlas Copco’s Drilling Solutions for the delivery of four large blasthole drills. In 2011 feasibility studies were initiated to expand Los Pelambres, which were finalised in 2013. One of the results of this research was that it became necessary for the mine to modernise the fleet in order to increase productivity and introduce new technologies, which have been developed in the Pit Viper series.
“We are confident about the productivity of Atlas Copco’s equipment as well as its progress in technology that has been demonstrated from the start of our operation,” said José Las Heras, Drilling and Blasting Superintendent from Los Pelambres mine. The executive added that Atlas Copco offers, within the large blasthole line, the electric and diesel versions. “With regard to the latter, we are very pleased and we tested its versatility and mobility within the pit,” he concluded.
In addition to the four blasthole drills on order, Minera Los Pelambres has two Pit Viper 351 electric and three Pit Viper 351 diesel rigs. The new drills will all be installed with Atlas Copco’s Rig Control System, which is computerised and automated rock drilling software.
“We’re excited about the opportunity to continue working with Minera Los Pelambres in this very strategic South American market,” said Peter Salditt, President of Atlas Copco’s Drilling Solutions division. “Our dedication to increasing the technology capabilities of our drills, and building a highly mobile, versatile unit is what attracted Minera Los Pelambres to us once again. This illustrates our presence in the region and our dedication to the blasthole market.”
Atlas Copco also recently launched the Pit Viper 311 large range rotary blasthole drill. The PV-311 has the capability of drilling 228-311 mm holes with a clean hole single pass depth of 19.8 m. Productivity is heightened through improved tramming, feed, and retract speeds, in addition to decreasing the time to perform non-drilling added functions of the machine, such as setting up. Atlas Copco has reduced the amount of downtime for preventive maintenance by up to 50% with the introduction of the remote filter rack and ground level service interface where all fluids can be filled or drained, and provisions for live sampling. It also has a new cabin with improved operator visibility and comfort, in addition to additional safety elements in the design. Drivetrain options with both Tier 4 and Tier 2 diesel engine alternatives are offered with the Pit Viper 311. The tower is structurally similar to the Pit Viper 351, but is deeper to accommodate larger sheaves for either single-pass or multi-pass applications, which means longer cable life. Atlas Copco incorporated full tower access with a ladder, harness, safety lines and tower infill, including a ladder that provides access to decking in the tower above the rod changer when the tower is horizontal. Atlas Copco offers a number of options for the Pit Viper 311, including a patent-pending automatic hydraulic clutch designed to decrease fuel consumption during non-drilling operations. In addition to standard safety and interlock features, the unit’s Rig Control System supports auto-level, auto-drilling, GPS hole navigation, and wireless remote tramming. A multi-pass version of the Pit Viper 311 known as the Pit Viper 316 will be released later in 2014. The Pit Viper 316 will drill to a depth of 90 m using a five-rod carousel with 15.24 m drill pipe.
In Russian drill rigs, the period October to December 2013 saw three IZ-KARTEX rotary electricdrilling rigs of model SBSH 270A mounted and commissioned at iron ore and copper operation in Asian mining enterprises. Installation of the machines was supervised by IZ- KARTEX together with drive system developer United Energy and the compressor unit developer VNIIkompressormash, based in Ukraine. Technical support and training is being carried out by IZ-KARTEX experts during 2014. The newest model available for the past few years from Rudgormash is the SBSH 250D, which unlike other large rotary blasthole rigs in its range is a diesel machine, so does not have to be linked to a cable, making it much more flexible and portable. It allows the use of large powerful rigs in remote parts of mines which may not have electrical infrastructure set up.
Top hammer and DTH track drills
The ex-Terex Caterpillar top hammer track drill factory in Denison, Texas, has had a major overhaul and revamp making it much more efficient and productive, with more Cat components incorporated into the range. Added to this, Caterpillar’s global network of mining dealers are now fully geared up to support the drills with drill parts in the Caterpillar supply chain. In models, Caterpillar has just announced the new MD5150C track drill, the first of the C Series drills, which have Cat components and are available from local Cat dealers who also service the drills. The MD5150C delivers “top-of-class power and high airflow” for fast, efficient drilling of holes from 101.6 mm to 152 mm in diameter. The MD5150C offers a choice of three different rock drills, patented carousel rod changer, ergonomic cab and many other features that boost productivity and reduce operating costs. Compared to the MD5125, which the MD5150C will replace, the new drill has 18% more power, a compressor that can deliver 33% more air volume and 40% more air pressure, 19% faster tram speed and 40% greater ground clearance.
Cat states: “High reliability, long life and low ownership costs characterize the MD5150C rock drill. With less than half as many moving parts as competitive rock drills, it is a simple, reliable design that offers dependable performance and exceptional durability. Caterpillar is the only manufacturer offering rock drills designed to be serviced on site—to reduce downtime and control costs. Service doesn’t require a clean room, and there’s no need to incur freight costs to ship the rock drill to the OEM for maintenance or to keep a spare rock drill in stock to accommodate maintenance downtime.
The rock drill also features an automated lube system, which eliminates the need to stop the machine for manual greasing every two hours. Three different rock drill choices enable matching the selection to the application to achieve the highest production rate.” The standard rock drill on the MD5150C is the HPR5128, which uses 51 mm drill steel. Also available are the HPR6832 rock drill, which can use 68 mm speed rod, and the HPR6030 designed for 60 mm drill steel.
The rod changer and feed assembly have seven patents pending. The system holds six rods and accommodates two lengths and multiple diameters of drill steel. Powerful dual-rod grippers and a unique gate design let the rod and gate move simultaneously, reducing cycle time. The rod changer is supported by a sturdy feed and heavy-duty 2.7 m boom that extends to 3.3 m for larger pattern coverage with fewer setups. Because the carousel rod changer weighs less and holds more rods than linear models, the boom extension can reach farther and drill deeper while maintaining stability. Holes can be drilled within 610 mm of the highwall, which is 50% closer than with a linear rod changer.
The heart of the model is the Cat C11 engine rated at 287 kW at 1,800 rpm. Designed for high performance and excellent fuel efficiency, the engine meets US Tier 3 and EU Stage IIIA emissions standards. The high-horsepower engine works as a system with a high-capacity air compressor to optimise air flow. An oversized, high-efficiency cooling system further improves performance and life. To further improve operator productivity, the machine is equipped with a smart drill monitoring system that tracks changes in rock formation and automatically adjusts impact and feed pressure based on hardness of the rock. Anti-jam, anti-plunge and anti-plug capabilities keep the track drill working efficiently and extend drill string life.
The model has a simple component layout and convenient service access. A walk-in service station provides easy access to major service points for the engine, compressor, air conditioner, hydraulic valves and more. A boom-mounted camera provides a view of the front of the drill while working inside the service centre. In addition to its serviceable design, the new track drill leverages exclusive Caterpillar technologies that maximise uptime. Cat Electronic Technician speeds the troubleshooting process, improving repair accuracy and reducing downtime. Cat Product Link allows remote monitoring of machine location, service metre hours, fuel usage and other critical factors.
The Atlas Copco FlexiROC T45 top hammer surface drill rig, along with its new COP 3060 rock drill, is “flexible yet uncompromising” according to the company, when it comes to fuel efficiency, while the COP 3060 further enhances drilling capacity. Like the ROC F9 before it, the FlexiROC T45 is described as “an efficient, production workhorse that offers high availability in a variety of applications.” Field studies show that the FlexiROC T45 with fixed boom uses half as much fuel as its ROC F9 predecessor using the same rock drill, depending on rock conditions. Additionally, the new rock drill COP 3060 mounted on a fixed boom and aluminium feed manages large diameters using the T60 drill string with high performance and reliability.
The new rig is based on a proven platform designed with a number of solutions to effectively reduce unnecessary energy losses and increase productivity. During operation, the operator can adjust the airflow and the dust collector fan speed according to actual working demands. The speed of the engine and compressor are then adjusted automatically.
The FlexiROC T45 also has 50% fewer hoses and 70% fewer couplings compared to similar rigs on the market. The hydraulics and electrical components are positioned close to their functions, making them easier to service and maintain and reducing the risk of leakage. The hydraulic tank is almost 60% smaller than on previous models, making it economical to use biological hydraulic oil without increasing total costs. The engine on the FlexiROC T45 meets Tier 4 environmental standards. A Tier 3 engine is also offered.
“Field testing has proven and our customers confirm that the FlexiROC T45 uses half as much fuel as its ROC F9 predecessor, using the same rock drill in similar rock conditions,” explained Maurice Hunter, Business Line Manager, Surface & Exploration Drilling Equipment. “Additionally, the new rock drill COP 3060 mounted on a fixed boom with aluminium feed produces larger diameter holes using the T60 drill string with outstanding performance, reliability and fuel economy.”
Mining companies operating in parts of Canada need equipment that will reliably and efficiently withstand extreme conditions, with temperatures dropping as low as -50°C, forcing companies to run equipment around the clock because, if stopped, it can freeze and take hours to thaw and restart. Sandvik Mining works closely with Canadian Royalties to equip several minesites located in the Nunavik region, which refers to the northern third of the province of Quebec where harsh conditions exist almost year-round. Canadian Royalties is a Chinese-owned and Canadian-run company based in Quebec. Since 2001, it has discovered numerous nickel-copper-cobalt-platinum-palladium-gold deposits which collectively form the Nunavik Nickel Project. The project was initiated in 2007. Given the harsh conditions in the area, the company looked to invest in mining equipment that would withstand subzero temperatures while running around the clock. To help achieve this goal, it purchased Sandvik’s DTH drills including two DR500 rigs that are equipped to handle these conditions.
The Sandvik DR500 series rigs are high-pressure DTH drills known for their productivity, durability and flexibility. Sandvik Mining bought the rights to the DR500 series surface drills from Cubex (which it went on to acquire last year) in 2010 and celebrated the official handover of the 100th Sandvik DR500 series drill in 2013. The drills are produced at Sandvik’s Canning Vale facility in Australia. Sandvik bought the rights to the DR500 series of surface drills from Cubex Ltd. in 2010, and has since produced them at a rate of about one machine per week. The diesel-powered, self-propelled, crawler-mounted drills are specially built for continuous drilling in extreme environments. The DR500 series also offers high operating pressures, which are critical to maximise the penetration rate when drilling harder rock. Sandvik states: “The rugged dependability of these drills and the customised cold-weather packages make them a perfect fit for environments like those in Nunavik.”
Sandvik says that the DR500 series offers the most extensive range of cold weather packages in its class. These packages include heating fluids that run through the rigs’ pipes, oil heaters installed in the engines, a canopy around the equipment to keep the heat inside and more. There are three tiers of cold-weather features based on specific applications:
• Tier 1 – for operation down to -15°C
• Tier 2 – for operation down to -40°C
• Tier 3 – for operation down to -50°C
Canadian Royalties and Sandvik worked together to find the right mix, choosing the Tier 3 package and adding a skid-mounted 35 kW generator set to power the cold weather heaters. The Tier 3 package also includes an additional cab heater, engine heater, hydraulic tank, water tanks and pumps, hydraulic components, steel canopy enclosure for the engine and more. “We really appreciate the DR500s in operation because they’re doing the job,” says Jocelyn Marquis, Reliability Advisor, Canadian Royalties. “You don’t want to buy something that’s going to break down or that won’t achieve maximum availability. The Sandvik DR500 is built for this; it’s reliable and it’s doing the work.” While in a typical setting, a standard availability goal might be 90%, those numbers decrease in extreme climates such as the Nunavik site. Canadian Royalties set the long term availability goal for the drills at the Nunavik site at 75%, and the DR500s are expected to surpass that goal. In 12 months of production, the drills have consistently provided 73%.
The heavy rigs come in and out via boat, and icy conditions around the Nunavik site allow only a small window of time for transportation in and out of the area about three and a half months out of the calendar year. That makes customer service and predictive maintenance critical. The two companies have taken a partnership approach to this project, working together to create a maintenance program customised for Nunavik’s specific needs.
At CONEXPO 2014, Sandvik Construction unveiled a new and improved version of the former bestselling Ranger-series of surface top hammer drill rigs. The new version, Sandvik Ranger DX800, combines the strong heritage of Ranger series with the latest drilling innovations and a significantly smaller appetite for fuel. Known to many by their former name, Ranger, Sandvik’s DX series surface top hammer drill rigs all feature a revolving superstructure enabling large drilling coverage from the standard 17.6 m2 to an USA standard 26.4 m2. While able to rotate, the rig stability is guaranteed thanks to its innovative structure, keeping counterweight at all times on the opposite side of the boom. In addition to these, the rig features, for example, a THC700 drilling control system that automatically adjusts to changing rock formations and sends an optimal amount of power to the rock. This has been designed to ensure smooth rotation, solid rock contact and fast penetration in different rock conditions.
Low fuel consumption is another major advantage. “At Sandvik, we aim at continuously improving the energy-efficiency in our rigs, and low fuel consumption can be considered a distinguishing feature of the entire product line. The new Ranger DX800 is no exception to this rule. The new rig will significantly reduce our customers’ operating costs due to its low fuel consumption rates that are achieved with a new advanced eco-package and engine rpm adjustment”, says Pekka Kesseli, Vice President, Surface Drilling, Sandvik Construction. Another enhancement is improved tramming force, which has increased by over 10%.
The Ranger DX800 is equipped with a low-consumption and low emission Tier 4 Final Cat 7.1 engine (168 kW). Utilising DPF technology with a common rail-type fuel injection system, it is able to produce high torque with lower rpm level. In the Ranger DX800, the standard level of 1,800 has been dropped to 1,600 revolutions per minute, resulting in significantly reduced fuel consumption. On average, this translates into 5.5 litres/1.45 less fuel consumed per active hour.
Coming with the well-proven rock drill HL810T as a standard, it can also be upgraded by changing it to a high frequency HF810T drill. “The newer HF810T has successfully been on the market for three years in Scandinavia. It offers around 10% higher penetration rates and better hole quality than its predecessor”, says Ilkka Lahdelma, Product Line Manager Surface Drills, Sandvik Construction.
Sandvik Construction also unveiled a practical software tool for surface drilling process management, Sandvik Driller’s office. The advanced tool is aimed anyone who works with surface drilling management, in particular in small mining and quarrying applications, as it helps simplify the whole process, as well as managing it efficiently. Sandvik Driller’s Office software is a surface drilling planning and data management tool. It covers drill plan design, drilling data management and reporting. Driller’s Office follows the logic of the job site and features clear and simple visualisations of the drilling pattern and terrain models in 3D, greatly helping the planning process.
Sandvik Driller’s Office features a Drill Plan Wizard for quick creation of basic drilling plans, and a Drill Plan Editor for creating more advanced plans. In Drill Plan Editor, hole positions, floor level, inclination, direction and many more factors, can be adjusted independently as needed.
In addition, instead of utilising a mere default bench shape and form as in standard planning tools, Driller’s Office allow those to be adjusted in order to correspond to the actual existing shapes and forms. A measurement tool and specific markers define the correct spot to start drilling.
The drilling process is further enhanced with the data management features of the Driller’s Office. The tool collects drilling plans and drilling data to a single project file. All the information on realised drilling results is available as real time feedback to the planning process. Adjustments to the existing plans are designed to be simple. Communications to and from the rig is handled over a mobile data connection. Sandvik Driller’s Office also includes reporting tools: reports on drilled hole coordinates, drill plan and drilling are available. Sandvik Driller’s Office tool is available for all TIM3D-ready surface drills.
Drill tools and bits
The grade of an orebody is rarely constant. It can be more concentrated near the surface and dissipate as the drilling samples reach greater depths. Grade control drilling helps to define the economic limits and determine where the mineral is abundant or too scarce for a return on investment. The most economical method to carry out grade control is Reverse Circulation (RC) drilling. Mincon has been involved in the design and manufacture of reverse circulation drilling tools since the early 1990s. In 2006, Mincon started the design and manufacture of our current range of RC tools. The Mincon MX RC hammers and bits were the first range produced and quickly gained traction in the marketplace. The MX5456 and MX5053 became widely used by a lot of exploration drilling companies. In 2010, the Mincon MX range of RC hammers came to prominence when the MX5053 hammer was used to drill the three lifeline holes that found the 33 Chilean trapped miners. Mincon started the design of the MR range of RC tools early in 2010 and since their launch the tools have quickly been accepted by the industry for their performance in RC exploration, grade control and pit extension exploration drilling.
Mincon believes that the MR range of hammers have some of the industry’s highest production rates in both deep and shallow bore RC drilling, “the most robust industry shank design and the lowest wear rates on all internal and external wear components.”
The MR range encompasses the most popular drill diameters for RC exploration and grade control drilling. The MR132 hammer drills from 137 mm up to 146 mm holes and covers deeper drilling requirements while at the same time maximising the available air output providing the industry’s fastest drilling rates. The MR120 and MR116 cover from 121 mm up to 143 mm drilling with high drilling efficiencies utilising available rig air or with boosters. Mincon states: “The MR range is ever expanding and there will be other additions to the range that will meet and best utilise all of the latest rig and compressor specifications. For grade control drilling the MR range of hammers offer many benefits to the end user. In high matrix wearing ground conditions commonly seen in grade control operations, Mincon can supply tungsten protected chuck sleeves to maintain a proper seal for better sampling ability. A proprietary heat treatment process extends the life of sample tubes maximising their service life. Mincon offers the largest range of face configurations to suit all different kinds of drilling conditions and the industry’s most robust drill bit to withstand the harshest drilling conditions.”
Rockmore International introduced the ROK 250 – a new 50.8 mm class DTH hammer at CONEXPO 2014. This new addition to the broad range of Rockmore’s high performance DTH hammer line is considered by the company “to be the first 2 in class DTH hammer ever developed to operate under high air pressure levels up to 24 bar and beyond.” With a 66 mm wear sleeve diameter, the ROK 250 is designed to drill 76 mm to 89 mm diameter holes at high penetration rates.
“We recognised a niche market segment in the DTH drilling sector that could utilise higher air pressure input levels to improve hammer penetration rates and drilling performance for hole requirements as small as 76 mm,” said Pejman Eghdami, Executive Vice President of Rockmore International.
Traditional 50.8 mm DTH hammers suited to drilling 76 mm holes are not designed to withstand higher operating air pressures and are often limited to 10 bar. The low energy values at such pressure levels result in poor hammer performance and low penetration rates, thus increasing overall drilling costs and adversely affecting hole diameter selection.
“Our design team faced the arduous challenge of developing a compact DTH hammer to withstand the technical demands of utilising higher input air pressure to produce exceptional hammer performance levels similar to larger high pressure rated models,” comments Eghdami. “The ROK 250 is aimed at DTH applications for smaller diameter blastholes and small mining and quarrying projects that demand high drilling efficiencies and faster drilling rates by utilising larger compressors rated up to 24 bar and beyond.
The new ROK 250 model includes the patented Rockmore SonicFlow technology, which optimises airflow in the hammer. This is achieved by simplifying and streamlining the air paths to minimise detrimental back flow and turbulence, resulting in maximum energy to the piston. This optimised energy level is transferred to the bit and rock formation to promote high performance hammer characteristics.
Boart Longyear has just released its new BLH line of DTH drilling tools, including hammers and bits. The BLH DTH hammer range includes valved and valve-less models, with a full complement of DTH bits- John Nielson, Senior Product Manager told IM: “Customers have been asking for a DTH solution from Boart Longyear and the new BLH DTH hammer line will deliver productivity in the ground with the quality and reliability associated with Boart Longyear. As an example the new BLH5 DTH hammer is an innovative new design that utilises a compact form that reduces the hammer’s length over 30% and reduces the weight by 20%. It will lower the total production cost for the driller with increased productivity and lower cost bits.”
The company says that the BLH5 DTH hammer has been designed from the ground up with the customer in mind. Its high frequency, low vibration operation delivers better productivity in various ground conditions and it eliminates the need for problematic exhaust tubes or foot valves on bits. It also has the largest shank cross section available (nearly 50%) that resists breakage through the splines. The piston in the hammer has virtually the same mass as the bit, ensuring balanced operation with minimised vibration.
The BLH3 DTH hammer adds a “reliable and robust steel valve system” to increase productivity over valve-less hammers, while the valve-less BLH1 DTH hammer is “a great balance between simplicity and performance, with minimal moving parts.”
Boart Longyear says that the BLH DTH hammers are a good option for RC drilling and conventional DTH drilling. Boart Longyear offers 4 in to 20 in class hammers and bits, so the hammers can work in almost all DTH
applications, including geotechnical drilling, quarrying/mining, water well/geothermal, and mineral exploration. Boar Longyear offers DTH hammers, bits, and hammer accessories including lubrication systems and break-out benches.
Sonic drilling updates
Boart Longyear also provided a review of the latest with its sonic drilling rigs and solutions in mineral exploration and mining. Justin Warren, Senior Product Manager for ranges that include these product lines comments: “Since Boart Longyear has launched the LS™600 Sonic drill rig, we have sold a number of rigs to drilling companies. The quick adoption of the technology is a good indication that our sonic technology. The new BLH5 series DTH hammer is an innovative new design that utilises a compact form and methods are here to stay. We believe that sonic drilling will continue to grow within the mineral exploration drilling market. Drillers are becoming more comfortable with sonic technology while sampling heap leach pads and tailings. However, the ability to pre-collar a borehole with a sonic drill before diamond drilling occurs is also being adopted — especially with the need to drill deeper, as available minerals become scarcer.”
By using the LS600 sonic rig to pre-collar during diamond drilling, drillers can avoid using diamond bits at the beginning of the hole by allowing the LS600 to advance through the early stages of the ground formation. The LS600 has excellent penetration abilities, drilling through deep, dense and difficult overburden formations to pre-collar boreholes. Pre-collaring also provides a detailed continuous overburden sample. Once bedrock is reached, diamond drills can drill deeper for mineral exploration purposes, saving bit life and increasing efficiency.
Sonic drilling differs from conventional drilling methods because it lessens the friction between the ground formation and the drilling equipment. Conventional drilling methods use a combination of torque and thrust to cut into the ground, allowing the drill string to advance the borehole, whereas sonic technology creates a resonant energy that matches the ground conditions. This eases the friction and causes the ground formations to displace, shear, or fracture — depending on the type of formation — allowing the drill string to advance.
Warren adds: “It is a very effective way to drill in unconsolidated ground, because drillers need to adjust the sonic frequency only when encountering a new ground formation instead of switching out a drill bit. Sonic drilling is typically performed with dual casings and 100% in-situ core samples can be achieved. The drill string advances into the ground formation, and once in place the outer casing can be advanced. This protects the integrity of the borehole. The core is then retrieved via the core barrel. Once the sample is removed, the process of drill string advancement and retrieval is repeated.Compared to conventional methods, drillers can gather accurate core samples twice as fast with sonic technology and reduce waste by up to 80%, because no fluid, air or mud is needed.” IM
