A miniature solution to a large problem

The clearing of conveyor spillage is an extremely time-consuming, unproductive and laborious task. The Dugless 900 mini-loader may finally offer a solution to the age-old task of clearing aggregate and waste from hard to reach places. Damian Christie reports.

Whether you work in quarrying or mining, one of the most frequent problems of materials handling is spillage and blockage. Mining companies, quarries, power generation facilities and other processes operate vast networks of conveyor systems to effectively transport material withintheir operations. These conveyor systems areprone to material spillage, especially at transferpoints. In virtually all circumstances, safety and time constraints prevent the proactive removal of spillage from underneath conveyor belts, often until it is too late and spillage piles up, causing conveyor breakdown.

The conventional means of cleaning out and reclaiming some of the material spillage varies from manual labour through to automated aids. Quarry and mine operations may have up to five workers shovelling out the spillage because only a shovel can comfortably reach in and under a conveyor belt, a laborious and gruelling task that can take days. They may be able to employ a skid steer loader with T-bar scraper blade to lift and drag out some of the lost materials but the skid steer loader?s short wheel base and long blades make it implausible for clearing out spillage from a space that would require a man to crawl in on his hands and knees. Water hoses are another alternative but raise an environmental issue. For a material like iron ore, which can be returned to the belt for processing, it is also more feasible if the material can be reclaimed and recycled dry. Whatever the method employed, the conveyor belts must be halted, resulting in significant delays to production.

Occupational health and safety (OHS) regulations also do not permit personnel to work on, between or under conveyors while they are operating. Even when the conveyor belts are not running, workers at the very least can potentially sustain muscular and soft tissue injuries just from manual materials handling.

Lost time injuries currently cost Australia?s mining industry an average $196,000 per incident.

The answer to all of these issues may lie in a remote-controlled conveyor spillage cleaning device that is approximately 560 mm high, weighs approximately 900 kg, has a continuous powered 12 kW engine, can travel at 3.5 kph on rubber tracks and carries a standard capacity four in one type bucket with a standard capacity of 0.15 m3. It is called the Dugless 900.

The Dugless 900 is, in effect, a mini-loader that cleans and reclaims spillage and blockage in and under those hard to get to places below the conveyor belt. At 2242 mm long, 1050 mm wide and 560 mm high, it appears to be ideally suited to navigate under conveyors between 580 mm and 600 mm off the ground. It is highly manoeuvrable – more so than a bobcat – with an angle of departure of 20 degrees and can be remotely guided using a joystick-equipped IP65 Radio Hand Control. The remote control system complies with ASNZ standards 4240 (1994 Radio Remote Controls for Mining Equipment) and 1418.1 (1994 Cranes Part 1: General Requirements).

In addition to clearing out conveyor spillage and blockage, the Dugless 900 can also be adapted to other dangerous areas of minerals processing plants, including very hot and cold temperature situations, enclosed tanks or pipes, drains, and grain or chemical storage areas. In particular, at the request of customers in different industries, the machine is being adapted to be flame proof for underground coal mines and another for use on hot services in a furnace area.

The designer and manufacturer of the Dugless 900 is Graham Townsend, the founder and general manager of Perth-based mining equipment supplier and services company Minprovise. He said that the inspiration for the machine, which is patent pending in Australia, came from observing similarly remote-controlled ?stand on? mini-diggers, excavators and skid steers.

?The stand on style machines were more commercial or industrial but we felt they were basically too high for cleaning under conveyors and perhaps a little unsafe with their short wheel base and high center of gravity, and the operator right on top of the machine in a confined area. We had a look at quite a few other machines that already existed and came up with what we call now the Dugless 900.

?Part of what we wanted to do was make it a standard machine with the lowest possible height and to have it tracked so that it could meet all terrain conditions and be remote controlled. It had to be manoeuvrable and be limitless to the area it travelled. If you equip an attachment to a tractor or a skid steer loader, it?s only as long as the apparatus – if it is three metres long, that is as far as you can go, and if you were to have a driver attached to it, it becomes a little bit unsafe.

?It was important that there was not a person involved with the machine; it had to be remote so if something did happen, only the machine cops the damage, not the person. That allowed the machine to be susceptible to working in risky and isolated areas. If the mine site believes that it?s suitable or safe enough, they could use the machine in an area where humans are not allowed to go. This increases the site?s uptime – they won?t have to shut the machine down, or the conveyor down, or the building or vessel.?

Graham said that where it might take five people on a team a full day or more to clear out just a few tonnes of spillage, the Dugless 900 is capable of the same job within one hour. ?We had one customer in the Pilbara – Rio Tinto in Cape Lambert – reclaim 300 tonnes of iron ore spillage, which is quite dense, for the stockpile in a 12 hour period. I don?t think too many guys would achieve that much, not from where it was. The space between the conveyor belt and the ground was only 600 mm high so they would need to get on their hands and knees to get in there.

?We?ve had a Dugless 900 on hire with Transpacific at Queensland Nickel and typically they would use four guys for four weeks to do the job, and they had the one guy with one machine for four days, so it saved them quite a bit of money.?

Most significantly, the Dugless 900 can be used to clean conveyor spillage and blockages while the conveyor belt is still running. Graham said that it was unlikely that the machine could be damaged by falling material while it is doing its work.

?The machine is fairly robust; it will handle a fair bit of punishment,? he explained. ?The rocks can?t be too big, but most of the spillage is quite tiny stuff anyway. The machine is made of steel, it has hoods and covers on it. The controls are very finite so you can sneak in and grab and come out; you are pretty much in control of the machine. If something went wrong, you?re only going to damage the machine, there is no person involved.

?Some operations may opt to use the machine when the conveyor is shut down. It will differ on a case by case scenario, where they would do the risk assessment on it and evaluate whether it?s safe for the machine, the operator and the business for the Dugless 900 to be operating in that area.?

Graham added that the Dugless 900 was designed with an emphasis on safety. To date, Minprovise has trialled a number of safety features with its customers, including a personal proximity transmitter, which could be worn by the operator ?so if the machine came too close to the operator or vice versa, it would switch off?.

Minprovise is still perfecting this technology, so this is not a feature that is currently available. However, if the operator tilts the Radio Hand Control, it will automatically shut the Dugless 900 down. The hand control is also equipped with an ?anti-gravity? feature, which means that if it is dropped or the operator slips and falls, the machine will also shut down. There can be no danger of the machine going rogue around the quarry site!

Minprovise has over the last three years sold four Dugless 900 units to customers, with another 10 available for sale, and currently have seven on hire or available for demonstration hire. Rio Tinto in Cape Lambert, in WA?s Pilbara region, has purchased two of the four units sold. It specialises in four different types of iron ore, estimated at 80 mtpa, which is processed, stockpiled, reclaimed and loaded onto ships at the port two kilometres from the Point Sampson Peninsula.

Eddie Kovac is the day crew production supervisor at Cape Lambert who is responsible for cleaning and reclaiming the conveyor spillage.
Eddie said the Dugless 900 enabled his team of 20 to more easily clean under conveyor belts while they are operating. ?We don?t introduce water so we can re-use the product straight away, rather than wasting it. We are saving on water, saving on man hours and it?s a very safe

Another of Minprovise?s customers – Port Waratah Coal Services – trialled the Dugless 900 over eight weeks, with the view to eventually purchasing a unit. The machine worked in conjunction with a bobcat to clear sections of the operation?s eight one kilometre long stacker and reclaimer conveyors. Port Waratah runs two terminals in Newcastle, with a combined output of 95 mtpa.

Mark Ryan, who supervises a daywork crew of seven at Port Waratah?s Carrington terminal, stated that in a single day, an underbelt scraper would move along a 200 m section of the conveyor system, ?getting into all the easy, accessible spots? and ?then we would have the Dugless 900 come in behind it and it would get in behind all the pipework, electrical wires, junction boxes and  middle section of the conveyors that are side by side.

?Using those two, we found that you could cover a lot of ground. If you just use the Dugless 900, it?s not quite as quick as the scraper, but if you are using the two it works really well. We have another bobcat working in between the two machines, clearing the roadway of the material they are reclaiming.?

Mark said that the Dugless 900 would make a marked contribution to the Carrington terminal?s productivity and health and safety. ?The good thing is we didn?t have to stop any production because there was enough clearance to get the Dugless 900 under the conveyors. You can also lift the bucket up and there is a fair 200 to 300 mm between the machine and the bottom of the conveyor. The Dugless 900 has totally eliminated any manual handling that you have to do, so now we can just keep going and a guy can stand away from the Dugless 900 and the conveyor belt, so there is no risk to the operator.?

He added that the machine also was very easy for his crew to operate and that Minprovise provided training. ?Graham Townsend came in and spent four days with a couple of our operators and trained them on how to use it. They found it fairly easy to use. They were already experienced with bobcats and loaders, so it didn?t take them long to pick it up.?

In addition to Rio Tinto Cape Lambert and Port Waratah Coal Services, FMG Cloudbreak, BHP Yandi, Newmont Boddington and Queensland Nickel have all wet or dry hired the Dugless 900. It has also received inquiries from customers in the US, the Netherlands and Chile. Graham Townsend said they had all been ?amazed at how much work it can do. Now when they do their job hazard analysis and identify a risk, they can either remove it or eliminate it or engineer it out and the Dugless 900 will take care of the engineering part of it?.

Graham Townsend said that the Dugless 900 has attracted some expressions of interest from quarry customers – notably a large quarry operation near Goulburn – although he believes it may be better suited to larger quarry operations, which may have up to 40 transfer points, rather than smaller quarry operators, which may only have three.

?For conveyor systems where there is quite an incline, going from a transfer point up into a bin, it is only the last several metres that may need one of these machines, and even then a larger machine like a skid steer loader may do that work,? Graham explained.

?You can still do that job but the conveyor may only have three transfer points, whereas on a large quarry they may have 40 and the Dugless 900 would have more work to do. The people who are more interested in the Dugless 900 are the ones with the overland conveyors, the long horizontal ones, yard conveyors, stacker reclaimers, tanks and vessels. A large quarry may be interested. If you?re operating a kiln or hot area ambient stations for cement, where the temperature is greater than normal, the Dugless 900 could also get in there and do that work as well.?

Graham said that research and development on the Dugless 900 is continuous and that Minprovise will be introducing five new models over the next two years. Minprovise will also be introducing a bigger brother – the Dugless 1200 – for the underground mining market. Graham said that it was not outside the realms of possibility that Minprovise could customise the Dugless 900 for quarrying applications.

 ?We have customers in the aluminium and the coal industry that want us to adapt it,? Graham said. ?We?re using the basis of the machine to adapt it to task-specific requests. We will do special attachments, if they want to attach something special, for example, removing the bucket and putting something else in its place. If a client has a problem with lifting a steel cable, we?ll adapt our machine to do it for them.

We have the base machine there and we?ll engineer the attachment to suit their needs. We do special engineering projects, little customised jobs here and there. It?s part of our business, so if we can use our base model machine and adapt it, then we?re interested in that. We could use water cannons on it or sucker trucks or hooks or forks. If one guy wants to put a fork on the front to move stands around from underneath a large machine, we can do that for them as well.

?Once a customer has used a Dugless 900, it is difficult not to have one for use,? Graham Townsend concluded. ?If you were cleaning spillage with shovels and other ways before, once you get one of these machines, it becomes a better solution.?

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