Category: Methods

Building Thailand’s Infrastructure

Posted on by Jari Silver

Power generation, irrigation, road construction, railroad tunnels – when it comes to building the backbone for Thailand’s economy, Right Tunnelling Ltd. is playing an active part in it.

Founded in 2000, the first project Right Tunnelling undertook was a tunnel excavation for the massive Khun Dan Prakan Chon Dam construction in the province of Nakhon Nayok, initiated by His Majesty the King. Since the completion of the dam in 2005, the local communities have enjoyed a constant supply of water for irrigation, and damages caused by flooding have decreased. The dam itself has become a major tourist attraction, with fishing and other outdoor activities.

Since the beginning, Right Tunnelling earned a reputation as a reliable contractor for civil engineering projects and has grown into the leading tunnel contractor in Thailand, with operations also in the neighbouring Laos and Myanmar.

Similarly, Robit has earned a reputation as a trusted partner for Right Tunnelling, providing them with Robit rock tools such as drill bits, rods, couplings, and shanks, as well as BulrocRobit hammers.

– Our cooperation with Right Tunnelling has been really smooth for several years. We have frequently visited their jobsites in Thailand and Laos to gain insight about their challenging drilling conditions so we can design the optimal tools for them, says Antti Mäkinen, Sales Director, Southeast Asia.

The latest jobsites where Robit’s tools have been put to the test include a railway tunnel, commissioned by the State Railway of Thailand in the province of Saraburi, the Maetaeng-Maengad water tunnel near Chiang Mai, and a headrace tunnel for a diversion dam in a hydropower project in the Bolikhamxay province in Laos.

Breaking Records in a Silver Mine

Posted on by Jari Silver

By the summer of 1546 Juan de Tolosa, a Spanish Basque conquistador, had grown frustrated. He had led several expeditions in search of silver in North-Central Mexico, with little success other than a handful of silver-rich rocks he’d obtained from local natives. On September 8th his luck finally changed.

De Tolosa had hit a mother lode that soon turned out to be one of the richest silver deposits in the world. Within a few decades, the mining camp he founded on the spot grew into a prosperous city called Zacatecas, which later became the capital of the state carrying the same name. By the 18th century, the state of Zacatecas produced no less than one fifth of the world’s silver.

Almost 500 years after de Tolosa, the silver deposits in the state of Zacatecas show no sign of depletion. One of the largest underground mines in the area is called El Saucito, near the city of Fresnillo, some 50 km north of Zacatecas City, owned by Fresnillo plc. Operational since 2011, it produces some 22 million oz (more than 620,000 kg) of silver per year, along with some gold, lead, and zinc.

To maintain and ramp up production, extensive mine development is constantly underway. In 2017, some 24,000 meters of rock will be excavated by the contractors at El Saucito. In such a scale, successful performance requires a reliable supply of all consumable parts of the drill string, such as bits, rods, couplings, and shanks.

Several contractors at El Saucito have chosen Robit’s tools, supplied by their local Robit distributor Rock Bits Tools. “It’s all about communicating and following up with the customer, so we can ensure we have the right drilling parameters and good conditions on the drill rig. Rock Bits Tools are doing a great job serving our customers”, says Sales Director Jorge Leal of Robit S.A.C.

Cominvi, one of the contractors Robit is serving at El Saucito, has reached impressive results with Robit’s tools in drifting and tunnelling. “Each drilling tool has a life expectancy relative to a specific mine or area. In El Saucito for example, a shank that lasts around 5,000 drill metres can be considered high quality. Recently, Cominvi drilled 9,196 metres on one of their drifters with our shank adapter COP1838 R38 038/435. To our knowledge, that’s a record”, Jorge says with a tinge of pride in his voice.

There may yet emerge new opportunities for breaking that record: the ore resources at El Saucito alone are estimated to last for another 25 years.

Picture: The Rock Bits Tools task force ready for action. From left: Gustavo Martinez, Jorge Rodriguez, Felipe Azpilcueta, Ricardo Castillo, Carlos Torres.

Granite – From the Bottom of the Pit to America’s Rooftops

Posted on by Jari Silver

Harvey, Irma, Maria – familiar names to all of those who watched the news on the hurricanes wreaking havoc around the Gulf of Mexico in 2017. As unlikely as it may seem, they are part of the reason why the drillers in a granite quarry in Arkansas are quite busy these days.

“I was introduced to Robit’s CEO at the Conexpo trade show in Las Vegas. I had a really good first impression of him and we got along good. We were having excessive wear of bits, chucks and hammers at our Arkansas site because of the material we were drilling. Robit said they could help us with that, so I decided to give them a try. It turned out my drilling foreman George Aday had already tested Robit tools, but as he had been buying them through a distributor, he had found the prices too high. Sometime after Conexpo, I visited the new Robit factory in Sherman, Texas and placed a first order for DTH hammers and bits. At first, we had some bits that did not work so good, but Robit did some redesign based on our feedback. Ever since, their products have worked better than anything we have used before. I would say we are very happy with Robit products and service as well.”

Dane Braden
President, Explosive Contractors, Inc.

Asphalt shingle is the most popular roofing cover in the United States – it’s relatively easy to install and not very expensive. The base mat of the shingle is saturated with asphalt and the top surface is coated with mineral granules. These granules add durability and protect the asphalt from the deteriorating effects of ultra-violet radiation. They also give the shingles their colour.

However, when a hurricane strikes, no amount of granules will protect a roof unless it’s carefully stormproofed. Each year, thousands of roofs in the hurricaneprone areas in South-Eastern US are damaged, if not entirely ripped away, by storms. This has boosted the production of roofing shingles and, consequently, the demand for mineral granules in the area.

Small clouds of grey dust rise from the ground as Justin Brandt operates the drill in his orange-red rig in a granite quarry in central Arkansas. He drills 5.75“ (14.6 cm) holes that go 14–15 metres deep into the hard rock. Later, the holes will be loaded with explosives and detonated; the blasted rock will then undergo a two-stage process of crushing and grinding, finally resulting in granules about 2 mm in diameter – the perfect coating material for asphalt shingles.

The orange-red drill rig belongs to Explosive Contractors, Inc. (ECI). Besides Arkansas and their home state Missouri, ECI operates dozens of drilling and blasting jobsites in Kansas, Illinois, Wisconsin, and Oklahoma, employing a fifty-strong regular staff and a large number of subcontractors.

Rich in quartz and thus very hard and abrasive, the Arkansas granite is a true challenge for any rock tool. Drill bits and hammers tend to wear out quickly. “Every time we need to shut down the machine to change bits, we lose production”, says Dane Braden, President and owner of ECI.

Recent months have seen a remarkable increase in production at the Arkansas site: replacing their previous Down-the-Hole drill bits and hammers with Robit tools has really made a difference for ECI. This did not happen overnight though: it required some testing, analysis, and product improvement by Robit until the optimal set of tools was developed. Today, the hammers are drilling up to twice as far as the previous ones.

This sounds like good news for all the other granite quarries in the area as well.

From left: Owner of ECI Dane Braden, his Drilling Foreman George Aday and Safety Manager Sam Crutcher

The Sense System goes to Java

Posted on by Jari Silver

Drill hole deviation is a problem most mining operations have had to deal with – until recently. Robit’s groundbreaking Sense System product line was created to address this issue. It has been extensively tried and tested in quarries and mines around the world, now including Indonesia.

In gold mines, blast hole sampling – analysing rock cuttings extracted from the drilled holes – is a common method of exploring ore grades. Accurate sampling allows for identifying ore zones and waste rock zones, which is essential for efficient mine planning.

Usually you have to settle for two dimensions when plotting the blast zones from sampled data. Also, the deeper you drill, the more the hole tends to veer off from its desired direction. Because of this drill hole deviation, you may end up with inaccurate sample data.

These are familiar problems at the gold mine owned by Bumi Suksesindo in Banyuwangi, East Java, Indonesia. That’s why the mining contractor and the blasting contractor at the site welcomed the opportunity to test Robit’s M-Sense system with PT. Marton, Robit’s distributor in Indonesia.

“We found that the M-Sense helped improve ore grade sampling. Normally you plot blast zones using two-dimensional data, but thanks to M-Sense, you get an instant 3D view of the drilled hole in the drilling pattern on a tablet screen. Any deviation from ore zone to waste rock zone is easy to spot”, explains Sales Manager Frandy Widjaja from PT. Marton.

“Also, when you can measure drill hole deviation, you can avoid overcharging the blast holes, which improves safety in a free-face area”, Frandy adds.

The M-Sense system has also been tested at a cement mine in Citereup in West Java, with equally promising results. “At both sites we have received great feedback from the test teams: M-Sense is simple to use, light-weight, and easily operated by one person. That saves a lot of time and hassle in the measuring process”, Frandy concludes.

Picture: The test team at Citereup, from left: Benny Sofyan, Wijaya Surio, Frandy Widjaja (PT. Marton); Ronaldo Indra Putra,Andry Kurniawan (PT. Indocement); Sunyong Choi, Binn Lim (Robit Korea)

Setting new performance standards in Phalaborwa

Posted on by Jari Silver

There are hardly many mining sites in the world where you can see herds of elephants and buffalo roaming about. At the mining complex in Phalaborwa, right next to the mighty Kruger National Park in the northeast corner of South Africa, that sight is commonplace.

The vast Phalaborwa complex is host to several valuable minerals such as phosphate, copper, zirconium, iron, and vermiculite. Phosphate is a key mineral in fertilizers. Before the foundation of the Phalaborwa mine in 1951, the South African agriculture was dependent on imported phosphate rock. Today, South Africa exports phosphate fertilizers around the world.

Venter Drilling, a local family business, has been the drilling contractor at the site for some ten years. In early 2018 they were contacted by Robit SA with a proposal to test Robit’s DTH bits and hammers. Not being completely satisfied with the products of their then supplier, the owner of Venter Drilling, Pieter Venter, agreed to have a testing programme arranged. This was a win-win deal, as it would also provide Robit with genuine feedback on their products.

The first test run involved ten DTH bits and a DTH hammer. “On the outset we wanted to achieve 800 metres per bit and 8,000 metres per hammer”, says Len Botha, who does business development for Robit SA. “In the initial test, the hammer reached 10,767 metres. The bits reached an average of 1,198 metres, with the best one drilling down to 1,699 metres. The previous supplier had averaged only 811 metres per bit”, Len recounts.

This was, of course, extremely promising, but to thoroughly convince Pieter Venter, another set of tests was arranged. This time the hammer went on to do over 12,000 metres. The bit performance was consistent with the first tests.

“Robit tools managed to reduce the overall bit cost by 32 %. This was mainly due to the DTA type of design that we introduced: 18 mm buttons on the peripheral and 16 mm on the inside, with the three centre flushing holes”, says Len.

Phalaborwa holds reserves of some 2.5 billion tonnes of phosphate rock, or five percent of known world reserves. That means the elephants and buffalo will be continuing their friendly co-existence with the miners for quite some time in the future.

Taking ground in the Brazilian quarry market

Posted on by Jari Silver

Concrete is the most versatile and most widely used material for construction. In a typical concrete mix, as much as 60% to 80% of it consists of aggregates. Aggregates for the construction industry are the most consumed mineral inputs in the world – including Brazil.

“In Brazil, extracting aggregates is a key activity in the mining sector. The recent economically lean years saw a reduction in production volume, but the economy is now recovering step by step. This applies to the aggregates market as well – and Robit found an important partner to help advance our growth strategy in the country”, says Alexei Albuquerque, Distributor Business Manager for Robit in Latin America.

Paraná Drill was founded in 2001 to serve the quarry market with equipment, parts and consumables. Based in Curitiba, the capital of Paraná state, the company covers the south states of Brazil.

“I’m always looking for quality products with a good reputation. Knowing that Robit was searching for a new distributor for this market, I approached them Taking ground in the Brazilian quarry market and introduced Paraná Drill and our operation in the segment”, says Fabiano Buffon, the President of Paraná Drill.

“We then organized a test in our quarry to learn how Robit’s tools would perform. I had a really good first impression of them and the results were positive, as we’d expected. We are happy with the performance of Robit’s tools and the support their team provides”. Today Paraná Drill is a recognized company in the quarry market, especially in southern Brazil. The market has great growth potential but also faces challenges.

“In addition to contending with our competitors, we need to deal with import duties, long-term customer financing and great variation in exchange rates. Having a partner with cost-effective high-quality products certainly helps”, Fabiano Buffon concludes.

Picture: Mikko Vuojolainen, VP, Robit Americas (left) and Fabiano Buffon, President, Paraná Drill

Marina gets overhaul in Britanny

Posted on by Jari Silver

In the late 18th century, France’s revolutionary government was in its prime. Napoleon’s star was rising and his armies swept through Europe. Napoleon himself knew that “armies march on their stomachs”. The government offered a 12,000-franc prize for the invention of a method of preserving food during long military campaigns. This would later have far-reaching impacts on the small Brittany village of Quiberon.

After years of experimentation, Parisian confectioner Nicolas Appert discovered that the combination of heat and air-tight packaging prevents food from getting spoiled. And so canning was invented – and Appert pocketed a nice sum of 12,000 francs.

Not long after, it was discovered in Brittany that tin cans were also a convenient way of preserving sardines. In the 19th century, Quiberon became the leading harbour for sardine fishing and the production of canned sardines in France.

Quiberon’s canned sardines can still be bought today, even online, but sardine fishing as a livelihood gave way to tourism a long time ago. Nowadays, the charming Port Haliguen is an important marina for recreational boaters, with more than 1,100 moorings and 11,000 overnight stays a year. Next to the marina lies a long stretch of beautiful sandy beach.

Originally built for fishing boats, the port was being stretched to its limit in terms of growth. The port’s infrastructure and installations are past their prime, and natural silting has made the harbour basins too low for larger boats.

A massive renovation project is currently under way in Port Haliguen: Its two harbour basins are being dredged deeper, the quays and pontoons are being completely redesigned, and additional moorings will be installed. In the first phase, the goal is to remove more than 50,000 cubic metres of clay from the basins. The clay will be used as filler in a new parking area that is to be built.

The contractors on the project are VINCI Construction Maritime et Fluvial and Eiffage TMF. The harbour foundations are constructed as a combi-wall structure, where steel piles are drilled into the seabed as load-bearing structures and steel sheets are installed in between them to form a wall. Robit was in charge of the technical solutions for the combi wall, under the leadership of Senior Specialist Kari Juntunen and Distributor Business Manager Taha Laissaoui. “Together with VINCI, we came up with the best overall solution, including equipment and operating methods. And it proved to be a winner: the piling was a great success,” recounts Taha.

A total of 460 piles with an average length of 15–18 metres were drilled. Some of the piles were delivered by the Finnish company SSAB. Robit’s delivery included casing systems (DTH-ROX SR 863/23), a robust 24-inch hammer and shock absorbers.

The port modernisation project is massive, and for the time being, the screeching of the seagulls is drowned out by the rumbling of excavators and drills. Port Haliguen should be ready to welcome travellers in all its renewed splendour in 2020.

DTARobit DR43 Reverse Circulation Hammer Complete the Set

Posted on by Jari Silver

DTARobit Australia have completed trialling of the new DR43 Reverse Circulation hammer.

The DR43 has an overall length of 1105 mm and weighs just 45 Kg without the bit, making it a manageable weight, reducing the manual handling risk. It has a cylinder OD of 107 mm and runs bits in a range from 114 mm (4½”) to 127 mm (5”). The DR43 is designed to operate efficiently at pressures between 350 to 500 psi.

The hammer design promotes improved sample recovery in difficult ground conditions.

The innovative design of the DR43 allows for the Adaptor Screen, Check Valve Spring and Plunger, Adaptor Tube and Sample tube to all be removed through the top sub, eliminating the need to break the hammer down to replace any of these components. This significantly reduces the number of times the hammer needs to be broken out on the rig, making this a much safer and quicker operation.

The DR43 joins DTARobit’s family of proven RC hammers, the DR38 (Bit Range 102 mm – 114 mm), DR44 (130 mm – 140 mm), DR53 and DR53 Retention (133 mm – 143 mm) and the DR55 and DR55 Retention (137 mm – 149 mm).

The Robit Group is proud of its long and innovative history in the Reverse Circulation drilling industry. Remet Engineers and BulrocRobit both members of the Robit Group of companies are pioneers in RC drilling technology. Remet developed the world’s first dual wall drill pipe used in mineral exploration drilling and BulrocRobit developed the world’s first true reverse circulation hammer. This history combined with continual innovation means you can drill with confidence that the DTARobit range of RC hammers, bits and drill string will deliver your client a quality sample, every time.

The hammer has been trialled by respected WA drilling contractor Strike Drilling, in 2 separate locations. The initial phase of the trial was overseen by DTA Robit product support and design engineering personnel. The hammer has now been drilling successfully for several months and is now ready to go to market.

Clay Schmidt, Strike’s Field Operations Manager, has had excellent feedback, with the drillers using the hammer seeing increased penetration rates, better sampling characteristics and ease of operation compared to the competitor’s hammer. “The new design allows for easy assembly and breakdown of the hammer. The upper and lower sample tubes can be replaced without breaking down the hammer making it extremely easy to service in the field”, said Clay.

Introducing HEAVY DUTY AUSTRALIAN drilling consumable solution available worldwide!

Posted on by Jari Silver

GET MORE LIFE FROM YOUR DRILLING CONSUMABLES –

DTARobit heavy duty drilling consumable solutions are available globally for mines and quarries. Our DTARobit products are Australian engineered solutions designed by drillers for drillers. These mining focused hammers are widely used at major mining houses and are the preferred choice of drillers for their DTH blasthole and RC drilling programmes. Products have been optimized through years of close co-operation with our clients resulting in higher productivity, more drilled meters and therefore overall reductions of costs in their operations.

Please read more: DTARobit Heavy Duty Series 2017

TGB and Robit made the “impossible” sheet piling possible

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Overview

A Swedish company TGB had major difficulties in sheet piling through rocky boulders. With Robit’s pilot technology, the impossible was made possible.

The rocky terrain proved to be so challenging, that the company decided to pre-drill the holes with Robit® Multi-Use casing system and retrieve the casing (406.4/12.5; L=6000 mm) afterwards. In the same project some piles were permanent and with the Robit® DTH-RoX 3-1, the same pilot was used to complete the drilling with Eco-rings.

TGB was able to complete the project on time with controlled investment. Christer Wretman, our distributor in Sweden, says: “Impossible project was turned to success with Robit Casing System”.

Skanska and Robit kept a warehouse stable in Turku

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Overview

To meet the demands from the contractor, Skanska needed new drill technology for reinforcing the foundations of a famous warehouse with underpinning.

A long-time landmark in the center of Turku, Sokos Wiklund warehouse building, needed a total of 200 holes to be drilled with casing in the underground parking hall. Additional corrosion reinforcement and concrete were then installed inside the 219.1/12.5 Ruukki casing tube. Due to space restrictions set by the site, a small drilling unit was used. Drilling with a ring bit casing system was the only alternative.

With Robit Casing System, the drilling was completed in a very short time. With such an impressive outcome, it was decided to introduce the system to several similar projects in the region.

Robit and Sotkamon Porakaivo anchored a paperi mill to the bedrock

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Overview

A paper mill in Finland needed altogether 58 holes for foundation reinforcement with depth varying from 12 to 16 meters. The terrain over bedrock was difficult, but Robit Casing System handled it fine.

Sotkamon Porakaivo had a challenge with the job of casing drilling to the bedrock and then drilling one meter into the bedrock itself. The first six meters of the formation consisted of sand and gravel. Blocks of granite and grillage (wood, clay and gravel) had also to be dealt with.

Robit® Casing System was the preferred technology due to its ability to drill difficult formations. Casing tube of 139.7/5.6; L=3000 mm was used. A 90 mm diameter steel bar was inserted and grouted to each hole. The end result was that the drilling went smoothly despite the difficult drilling conditions.

Pipe pile wall construction work at Viljuisk hydro power plant in Yakutia Russia

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Overview

The goal of this project is to secure the reinforced concrete bottom and wall slabs of the incoming water channel and also to prevent their final breakage and flushing away by water flow.

The project owner is Russian State energy company «Rushydro» and it is projected by OAO “Lenhydroproject” engineering company from St. Petersburg in cooperation with Robit Rocktools. From Robit´s side the project was supported by Mr. Kari Juntunen and Mr. Juha Sorjonen. The project also included underwater drilling which was made during the operation of hydro power plant.

The project included the following stages:

  • diving operations in the depth of 8-9 m with water flow rate of 0,5 – 1,0 m/s
  • drilling through 1,7 – 1,95 m reinforced concrete bottom slabs using 1 m diam. diamond bit
  • removal of 1 m diam. pieces of reinforced concrete slab from the bottom
  • construction of 720 mm pipe pile wall (height 11,5 m) on the river bottom through the drill hole in reinforced concrete slab
  • concreting of the seam between the reinforced concrete slab and pipe pile wall
  • underwater concreting and installation of the pipe pile wall on the whole length of channel

After the operations above the complete pipe pile wall is installed according to the cross section of the incoming water channel of hydro power plant. This construction is used to prevent the breakage and flushing away of reinforced concrete bottom slabs what has already taken place during the last 20 years of operation.

Time of the project is 2 years but due to the working schedule of the power plant surface and underwater operations can be commenced only in July – September.

The installation of pipe pile wall was started in July 2013 by contracting company “OOO SU-299” from St. Petersburg. Till the end of September 15 piles were drilled and 20 m of pipe pile wall was installed. The method has proved to be successful and economical in the extremely hard working conditions of Yakutia.

From “OOO SU-299” company the project was managed by Mr. Vitali Korshunov, Project Manager and Mr. Vladimir Klimov, Development Director.

The following machinery was used in the project:

  • “BRAUN” diamond drilling equipment and tools
  • “ROBIT ROCKTOOLS” drilling technology and tools, Wing Bit DTH SF 720/10 N180
  • “COMACCIO” DTH drilling rig
  • “ROBIT” 18” DTH hammer
  • 200 t and 500 t barges, floating crane 5 t , a towing vessel

 

Piling without disturbing the neighbours in Stockholm

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Overview

Solna Arenastaden right next to Solna railway station needed support piles for passage over railway between Arena and surrounding buildings. The urban site called for extra care and Robit products.

The work site needed some 150 piles (220/12.5) to be driven to overburden ground, which tends to ”suck the water” due to numerous fractions. What’s more, there was a large sewage passing near the worksite, let alone railway and buildings. In this environment, any pollution would be no-no as well.

Due to ground type, air drilling would almost surely cause problems to surroundings. The use of Wassara W150 ensured fast penetration and created less noise. The project was finished with minimum disturbance.

New Robit horizontal drilling equipment proves its worth in Sweden

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Overview

Robit, in collaboration with our retailer Swedish retailer GDS Sverige AB, put our new HZ product series to test under a motorway ramp near Landvetter airport.

Robit has been developing the new HZ series for horizontal drilling in Sweden since the early 2011. Now, the new system was put through its paces under a motorway ramp, where a 24-meter hole of size 406.4/12.7 was drilled. The land filling under the ramp consisted partially of very large boulders. Because of the boulders and directional requirements, the drilling was a challenging test to our new HZ series.

Despite the rough terrain, the results proved successful. No problems occurred, and the drilling went as

planned. What’s more, the test drilling results have enabled the company to further improve the functionality of the HZ product line.

Lemminkäinen builds a new metro station with Robit

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Overview

The so-called West Metro is a major expansion to current underground railway system in the Finnish metropolitan area, stretching it all the way to Espoo. Lemminkäinen is in charge of building the Koivusaari metro station, complete with a kilometer of tunnel. As usual, Robit delivers the goods.

The project, involving much earth-moving and digging, takes place in an urban, unforgiving environment. “The location is challenging, so it is essential that all components needed for the work have high quality and reliability”, says Annina Peisa, Construction Manager at Lemminkäinen. “Our suppliers have a substantial impact on the success of our projects”.

Lemminkäinen and Robit have been co-operating successfully for the past ten years, and this site is no exception. The installation and drilling tools required for making excavations and supporting the walls with RD piles this are supplied by Robit. Thanks to our dedicated, knowledgeable service, the construction is well on the way, and expected to be finished on time.

No wonder Peisa is pleased: “Robit is a very customer-oriented partner”, she says. “If we have any problems in our projects, Robit will provide us with quick and professional service. They will come and check the situation on site as needed.”

Customer description

Lemminkäinen is a construction group specializing in building construction, infrastructure construction and technical building services. Its main markets are Finland and the Baltic Sea region. The Group employs about 8,400 people, and its turnover in 2011 was approximately EUR 2.2 billion.

Top Hammer Drilling

Top Hammer Drilling

In Top Hammer Drilling the hammer produces a percussive force on the drill rods or tubes, which is transmitted to the drill bit. The feed device is usually attached with a hinged boom to a mobile unit. The percussive system strikes the drill rod, for example 2,000-5,000 strikes per minute, and the rotation speed can be, for example, 60-200 rounds per minute. Together these elements make it possible to drill holes in the hard rock. The excess material (cuttings) is flushed up from the bottom of the hole by means of pressurized air or water. Top hammer drills are primarily used in mining, construction and quarrying of rock material. Top hammer drilling, combined with the “drill and blast” method, makes the whole excavation process extremely efficient.

Rotary Drilling

Rotary Drilling

Rotary drilling is a method of drilling that employs a sharp, rotational drill bit to bite its way through the earth’s crust. It relies upon high rotational speeds and thrust without percussion to achieve the desired effect and outputs. In rotary drilling, the rock is made to fracture by means of a combination of “pull down” pressure on the bit and rotational power “torque”. Weight is applied to gouge, chip and grind the rock. Tricone rotary bits are sometimes a good alternative to a DTH hammer. It is used in the construction, mining, and oil industries as well as water & thermal wells. Robit offers TCI (carbide buttons) and mill tooth configurations.

Reverse Circulation

Reverse Circulation

Robit’s Reverse Circulation (RC) products help you drill deeper and faster and importantly delivering high quality samples for your customer. Reverse circulation is achieved by blowing air down the rods, the differential pressure creating air lift of the water and cuttings up the “inner tube”, which is inside each rod. It reaches the “divertor” at the top of the hole, then moves through a sample hose which is attached to the top of the “cyclone”. The drill cuttings travel around the inside of the cyclone until they fall through an opening at the bottom and are collected in a sample bag.

DTH Drilling

DTH Drilling

A down-the-hole drill, usually called DTH is mainly a pneumatic powered rock or ground drill, in which the percussive hammer is located directly behind the drill bit, so the percussion mechanism follows the bit down into the drill hole. The drill pipes transmit the necessary feed force and rotation to the DTH hammer and bit, as well as compressed air for the DTH hammer. Air flushes cuttings up from the bottom of the hole. Drill pipes are added to the top of the drill string as the hole gets deeper. The piston directly strikes the impact surface of the bit, while the hammer casing gives guidance to the drill bit. The fast hammer impact breaks hard rock into small particles, which are blown up by the air exhaust from the DTH hammer.