Tag Archives: Dando Drilling

Heritage Minerals smashes Dando Terrier percussive drilling depth record

The Heritage Minerals team, led by Drilling Manager, Shane Charlton, has been achieving depths of 46 m with high-quality 86 mm samples using Dando Drilling’s Terrier percussive drill rig, the drilling manufacturer says.

The depth is a record for the Terrier rig, according to Dando.

Heritage Minerals is currently working on the historied Mount Morgan mine in Queensland, Australia. One of Australia’s oldest mines, Mount Morgan was active from 1882 through to the 1980s. In the process, tens of millions of tonnes of tailings were generated.

Today, these tailings present both a problem and an opportunity; a problem because they were subject to old, polluting technologies for processing gold, but an opportunity because they still contain reserves of gold, copper and other minerals.

Heritage Minerals is employing innovative processing technologies such as ReCYN, developed by partner GreenGold Engineering, to clean pollutants from the tailings and returning them to safe land.

It was this technology and the tailings recovery aim IM recently focused on for an in-depth article on Mount Morgan.

Heritage chose a Dando Terrier rig to sample the tailings at Mount Morgan for several reasons, Dando said.

“Foremost, the unconsolidated geology of tailing fines is very hard to sample with conventional rotary equipment,” it said. “The Terrier’s Duplex Sampling System, which is driven into the ground by a 64 kg anvil and simultaneously cases-off and samples, provides excellent recovery in this type of unconsolidated geology for metallurgical and in-situ density measurements.”

Charlton proved and refined the drilling method he used in the mineral sands of Kalimantan, Indonesia, where he sampled alluvials to over 20 m for lab analysis, Dando says. This is an impressive feat for a rig that has a large user base for geotechnical sampling, standard penetration testing and dynamic probe testing, most often at depths of less than 15 m.

More than doubling this to 45 m was no easy task, Charlton explained: “At depth, it took almost 10 minutes to trip the drive rods and retrieve the sample, but the quality of the sample and the economies in terms of cost per metre offset the sometimes slow drilling.”

Heritage has recently purchased a second Terrier rig from a Dando customer in Australia and Charlton has made some modifications to the design to facilitate drilling beyond the original specifications of the rig.

“We’ve fitted a permanent casing extractor to help pull sample tubes and casing if they get stuck, as well as modifications to assist with tripping rods more quickly,” he said.

To achieve these depths, the team are using a reaming method whereby they sample using an 86 mm windowless sampler tube, and then ream out using a larger 116 mm tube before returning to the 86 mm sampler to continue. This reduces frictional forces along the side of the borehole and abrasive tailing materials, according to Dando.

The percussive hammer system allows sampling without flush, minimising the need for cumbersome mud tanks or air compressors while preventing contamination of the sample or the environment, it added.

Dando to solidify industry reputation with new standout rig features

A change in management and direction is revitalising a more than 150-year-old drilling company serving the mineral exploration, water well, geotechnical, geothermal and offshore sectors.

Established in 1867, Dando Drilling International has made a name for itself with robust and customised drill rigs built to withstand the harshest of environments.

Mark Jones, Managing Director of Dando, has an anecdote or two to reinforce this.

“I was in Ethiopia in February and visited the country’s geological survey,” he told IM. “They were still successfully operating a Dando rig from the 1980s!”

Jones and Dando Chairman, Mark Slater, entered the company’s HQ on the south coast of England last year to head up the firm. This followed the acquisition of the company by a consortium of UK-based investors who took on the outfit from Canada-based Energold Drilling Group.

After getting his feet under the table, Jones, former Managing Director of Ingersoll-Rand in South Africa and CEO of numerous mining and exploration firms, set about revitalising the company’s fortunes.

Mark Jones, Managing Director of Dando

Part of his strategy was tied to bringing manufacturing capacity back in-house.

The company went some way to achieving that earlier this year when the opportunity to build out its machining capabilities with the acquisition of Unistates came about. Now integrated into Dando as Dando Engineering, this machining facility reinforces Dando’s supply chain as well as offers sale opportunities to other industries.

Such a move will help the company in its next phase of revitalisation.

“One of Dando’s historical strong points has been to meet customer requirements in the industry with bespoke rigs,” Jones said.

This is the case across all industries including mining, which, after water well drilling, is the company’s second biggest sector by value and accounts for around 40% of Dando’s business.

Bespoke comes with a price tag and significant component procurement and rig manufacturing time; attributes not all customers are willing to entertain.

At the end of 2019, Jones and his head of engineering discussed ways the company could appeal to a wider base by creating a new image, brand and product offering that leveraged Dando’s experience and industry reputation.

The pair started looking at how they could retain the ‘bespoke’ mantle yet maximise use of off-the-shelf components. Ensuring these components are modular and standardised would enable the company to accelerate the build and delivery time of its rigs.

“We need to design in the ‘manufacturability’,” Jones explained.

In the future, its new rigs will, for example, have far fewer hydraulic hoses, while more of the rig infrastructure will be pre-prepared in the assembly stage.

“If you standardise on the chassis and scale up, there is still a huge amount of flexibility with rig design,” Jones said.

The first rigs to be built next year will also have certain features that stand out from the average drill rig on the market, according to Jones.

Recognising the long lead time for large engines, the company is also looking to use smaller, more efficient engines, to cut the estimated time to delivery for its rigs.

This shift to smaller engines is also a reflection on the need for Dando to provide products that are more energy efficient and sensitive to the environment in which they will be used.

“If you look at any rig with an air compressor, much of the horsepower of the engine is around the compressor, but the compressor tends to only be used for a small slice of the day,” Jones said. “You are churning and consuming diesel and generating toxic fumes for often only a small amount of work.”

A fully customised offering will still be available to those customers willing to pay the time and cost premium.

“We will innovate, we will be doing things for the right reason, but equally we will have the capability to deliver what our customers want,” Jones said.

Some of this innovation falls into the category of remote rig operation, which Jones expanded on.

“Mining is well ahead of the curve with safety and environmental concerns, so we are seeing a much faster take up of innovations that protect workers and the environment,” he said. “Remote drilling and rod handling are increasingly more important, particularly for bigger rigs.”

Jones said Dando sees a time when rod handlers and attendant rod carriers, like its Mule track carrier, are standard in exploration drilling, reducing the risks to personnel on or close by to the rigs.

“In the shorter term, semi-automated rod handlers are of most interest, but we will offer fully-automated systems on our exploration rigs from 2021,” he said.

Dando’s customers are also looking for higher tier engines – up to EU Stage 5 – in line with rising ESG concerns, according to Jones.

“All our new rigs will cater for this demand and we are also seeing how we can reduce our carbon footprint by clever use of design and material choice,” he said.

With a range of coring, RC and multi-purpose rigs represented on all continents in the mining space, the Dando of new is taking the best bits of its more than 15-decade history and revamping them in a sustainable way for the industry of the future.