Tested tools: Robit DTH hammer and bits
Test location: Altyntau Kokshetau quarry, Kazakhstan
Client’s challenge: Finding an alternative for their existing QL6 DTH hammer: problems with the upper adapter not solved by the manufacturer
Reported by: Andrey Dak, General Director, LLP Robit Kazakhstan

Report:

At the site, Robit Kazakhstan has tested two QL6 DTH hammers, with 171 mm Robit DTH bits. Representatives of Robit Kazakhstan and Robit Russia as well as competitors’ technical specialists were present at the test. Each of 3 drill rigs had drilling tools from different manufacturers.

As a result, Robit hammers demonstrated excellent results, whereas the tested drill bits did not show the best performance. Therefore, Kazzinc acquired a batch of Robit hammers.

Once in operation, quality issues with the acquired DTH hammers arose: the lifetime of some of the hammers was 30 % less than expected. Lifetime expectation is set by the quarry; we accepted the challenge.

We took a customer-oriented approach and invited a technical specialist from Australia to Altyntau Kokshetau. In addition, two upgraded hammers and redesigned 171 mm DTH bits were sent. Using all the test data, we strove to manufacture the best fit for the customer’s ground conditions. The changes mostly concerned the hammer’s cylinder, make-up assembly, the DTH bit’s check valve and buttons. A second test supervised by our local Robit expert was conducted.

Eventually, thanks to our group’s teamwork and our desire to provide the best service, the performance became excellent again – even exceeding the lifetime expected by the contract. The upgraded DTH bits also showed good results, reaching their expected lifetime. The deal was secured.

Kazzinc decided to continue using Robit drill consumables. Starting from the beginning of 2019, a new contract for a batch of DTH hammers and DTH bits was signed.

Rolling grass plains and awesome rock faces rising up behind them – it’s like a scene out of a western movie. A monotonous pounding can be heard beyond the mountains. Yet we are not in the prairies and the bangs are not from revolver guns. The source of the noise is a Robit Hyper 181 Down-the-Hole (DTH) hammer striking deep into Australian soil, more precisely the mineral deposits of Narrabri.

Lucas Drilling Services, part of the Australian AJ Lucas Group Limited, is more or less halfway through a major coal mine project at the Whitehaven Coal company’s Narrabri North mine. They have drilled around 50 holes down to the bedrock, the deepest ones extending to 240 metres. Around 70 holes remain to be drilled.

Lucas Drilling selected for the project T120XD and Schramm T685 drill rigs equipped with the Robit Hyper 181 DTH hammer. The contractor requested a brand-new 18-inch Robit 181 from the local Robit dealer in Queensland, Dilong Drilling, with whom Lucas Drilling had already successfully collaborated for several years. Angus Simmons, Drilling Supervisor at Lucas Drilling, describes the operation as follows:

“We’ve used our Robit Hyper 181 DTH hammer in a Schramm T130XD drill rig for more than fifty jobs now without a single problem. Some time ago we upgraded our equipment with new Robit Hyper 181 DTH hammers and we’re now using them also in a Schramm 685 rig. We use the Hyper 181 model for hard and brittle basalt and other volcanic types of rock down to depths of 64 metres.”

After that, a 14” DTH hammer will go further down to 200– 220 metres to reach conglomerate of ancient petrified gravel. Finally, a 9” DTH will hammer away the rest, at a depth of between 220 and 240 metres.

AJ Lucas Group, listed on the Australian Securities Exchange (ASX), has more than 60 years of experience in the sectors of energy, water & waste water, resources and public infrastructure. Headquartered in Brisbane, Lucas Drilling has broad experience in engineering services, horizontal directional (HDD) drilling, drilling for oil, gas and coal, surface-to-inseam (SIS) drilling and many other areas of special expertise, making them one of Australia’s largest and most diversified drilling service suppliers.

Dave Crane, sales coordinator with Robit, spared no praise for the quality of work at the Narrabri North mine:

“The workmanship at the mine is solid testimony of Lucas Drilling’s know-how and experience, of Dilong Drilling’s technical support and special expertise as well as of the power and reliability of the Robit Hyper 181 DTH hammer. It’s truly a winning combo!”

Picture: The Schramm drill rig uses three different-sized hammers and drill bits for drilling a 240-metre-deep hole. Lucas Drilling Services relies on Robit’s DTH drilling equipment in demanding conditions.

Developing DTA’s drilling consumables to their current level of excellence was a long and hard learning curve. Looking back, it was all well worth it. These days Ausdrill is the one to raise the standards to its competitors.

David Hart, Area Manager at Ausdrill Ltd, recalls being one of the first customers to use DTA’s products:

“When I look back on the whole process, I realise now that this could not have been done without some ‘blood, sweat and tears’, and also not without close co-operation between Ausdrill’s and DTA’s personnel. The tight relationship between Ausdrill and DTA was a stroke of luck! DTA was able to make improvements and changes to the products on short notice, and Ausdrill was able to trial those changes just as fast. This made the whole experience less painful than it could have been. There was some frustration, but also satisfaction along the way to producing and developing a product that today will hold its own against the competition. It was a great learning experience!”

At the Super Pit operation we are required to drill approximately 190,000 metres per month. The size and depth of the holes vary, as does their purpose; we have 20,000 metres of grade control holes, 50,000 metres of probe holes and the remaining 120,000 are blast holes. Grade control holes are designed to define the ore body boundaries within each bench prior to blasting. The blast holes are loaded with explosives and the blast fractures the soil into pieces suitable for loading and hauling. Probe holes are designed to define the border
between safe ground areas and potentially unsafe areas, where old underground workings are present.

“Prior to Kalgoorlie becoming the ‘Super Pit’ in the late 1980s, there were many different gold leases owned by different prospectors and lease holders in the area. The majority of the individual gold operations across the Golden Mile (now the site of the Super Pit) were underground operations. The combined length of the underground workings is over 2,000 kilometres, and the size of each mine varies according to the era and methods used at the time. In the 20-plus years that Ausdrill has been working in the Super Pit, I know of one case where a drill rig partly fell into some old underground workings. It couldn’t be retrieved, so it was blasted and dug up with the rock. The operator survived the incident,” Hart says.

Ausdrill uses DTA products at all of their 10 drill and blast sites in Australia and also on some exploration division drill rigs. The most common products are the 4- and 6-inch blast hole hammers and bits used for drilling holes from 115 through to 165 mm. We additionally use a few 7- and 8-inch hammers for drilling hole sizes from 203 to 251 mm and reverse circulation hammers for grade control and RC exploration.

The manufacturing business in Australia is very challenging financially, and many companies have either left Australian shores and set up in India or China to reduce their costs or closed up shop altogether.

“Continuous improvement will be required to keep DTA’s products in the markets and to meet the competition headon,” Hart believes. “A lot of competition stems from the price dumping due to hand-made products from China and India.”

DTA uses robotic machines to contain labour costs, while still maintaining high reliability and proven quality in production. While it is apparent that more and more competitors are entering Ausdrill’s market, the company is determined to stay focused and have fun along the way. It is “cost per metre and reliability” that will win out in the end, Hart concludes.

Picture: KCGM Kalgoorlie Super Pit – Ausdrill has been the production drilling contractor at the Super Pit for many years.

In late 2016, Robit took a step to expand its foothold in the Middle East by establishing a sales company (Robit Plc – BFC) in Dubai, the largest city in the United Arab Emirates. The new sales company is led by Export Manager Juhani Sivenius.

What are the starting points for the operations in the Middle East?

Considering the size of the market, Robit’s sales in the area have been modest to date. The journey is only just beginning. We are currently focussing on presence to enhance visibility, and on availability, which is indispensable for growth. So we have a lot of footwork to do. We have achieved a few successes, which creates a good foundation for the future.

Tell us more about the successes!

Stevin Rock, the area’s largest quarry located in Ras Al-Khaimah, is my customer. Robit has a two-year agreement for the supply of wear parts for their entire DTH line. Drilling in Tel Aviv’s metro tunnel project in Israel will start during the summer using our forepoling tubes. The Turkish market is already looking good, thanks to my colleague.

What is Dubai like as a business environment?

The culture is quite colourful because of the wide variety of nationalities. Taking care of administrative matters can be a little slow and bureaucratic, but you get to used to it. My goal is to turn the operations in the area around as soon as possible by acquiring end customers and expanding the distributor network.

Picture: Cliff McGowan (DTARobit) giving instructions to Bharadwaj Ventaraman (Delta Corp Global, right).

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

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.