Productivity call answered

Cutting costs and lifting productivity: two of the big calls at any mine site, and big calls being answered at the huge sites in the Bowen Basin.

Cutting costs and lifting productivity: two of the big calls at any mine site, and big calls being answered at the huge sites in the Bowen Basin.

A quick look at how some mine managements are achieving these two objectives makes for an interesting read.

For Australian Mining, one of our contributing writers has assessed one of the vital activities that can make a significant difference with costs and productivity — picking up coal at the coal face and loading into the big haul trucks.

The overview is that conventional equipment and conventional thinking often encourages a continuation down the same line, whereas a pause, to look at an alternative concept, can often end up a new direction. In short, ‘thinking outside the square’ can provide beneficial answers.

Following visits to mine sites and comparing the performance of different loaders, some significant cost savings and productivity gains appeared to be there for some mine managements to seize.

It is the specifications and reported operational figures, gleaned from various sites, which presented the case for opening up the comparisons between different makes of loaders, particularly as the savings can run into figures around $200,000 per annum per loader!

To get a line on this outcome, a start point is the challenge set by LeTourneau with its design and points of differentiation, over and above the ‘same same’ features. It seemed appropriate to use LeTourneau as a benchmark.

Fuel burn

In this time of soaring oil prices, the issue of fuel burn rates highly. Looking at one case, where a Komatsu loader was working alongside a comparable LeTourneau, a possible annual saving of around $200,000 emerged.

In this case the LeTourneau L-1850 ( 25.3 cu m bucket) was using between 145 and 146 litres per hour, compared with a Komatsu W.A. 1200 that was near 200 litres per hour. Calculating, at the advantage of 50 litres per hour, at say a nominal 80c litre, for 5,500 hours per annum, a cost reduction of $220,000 per annum was possible.

Now these comparative figures were not based on a controlled scientific comparative trial, but the size of the ‘close enough’ saving makes for an overwhelming case.

How is it that the LeTourneau loader delivers such a different outcome? – It is based on a totally different drive system — an electric drive in lieu of a mechanical drive system.

In short, the electric drive system is based on a diesel engine to drive the electric generator / drive systems on each wheel. The net result is that the driveline involves no drop box, transmission or differential and the associated power loss. Another advantage is that the diesel engine runs at a constant speed, whether the loader is powering into a face or travelling to another face.

“You just don’t see that black smoke come out of a LeTourneau exhaust, as if its grunting,” said one person.

“And, you know with less fuel going through the motor, as well as it running at constant speed, the wear is significantly reduced, maintenance costs are down, there’s no escaping it,” he added. Clearly, a comparison with mechanical drive loaders and a LeTourneau will show a way to major savings.

Tyre wear

At one mine site a major saving with tyres was evident on their LeTourneau; it signalled a need to bury deeper for an explanation.

A difference of around 4,000 hours was estimated — mechanical drive loader versus an electric drive loader.

On examination, the figures were; the electric drive loader achieved 12,000 hours with a set of tyres whereas a comparable mechanical drive loader, at the same site, achieved around an estimated 8,000 hours.

Investigating further, it shows up that the electric drive system eliminates two of the three main causes of tyre wear — slippage and scrubbing.

Productivity issues

Tonnes per hour and haul trucks loaded per hour are two vital figures and it is a quick easy process to see the difference between loaders. A clear winner can emerge quite quickly.

First step, to assess where the productivity advantage lies, is a comparison of bucket capacity between competing makes.

Three makes of loader were compared: Komatsu, Caterpillar and LeTourneau.

Comparing ‘like with like’, off specification sheets for loaders typically seen in the Bowen Basin, shows: the Cat 994F with 17.96 cu m, the Komatsu WA 1200 with 20 cu m and the LeTourneau L-1850 with 25.3 cu m,

At some mine sites, the question of tramability is an issue … it can be a major issue and have a severe impact on productivity. Some sites require loaders to travel considerable distances.

What did emerge was a severe limitation with mechanical drive loaders.

At one site, a mechanical drive loader was seen to travel many kilometres, but it could only travel 2.5 km between cooling stops.

The loader had to cool down, and be tested with a heat gun, to ensure adequate cooling had occurred before starting on the next 2.5 km leg.

On hearing this, a check was made with the electric drive LeTourneau. No cooling stops required; the only matter that warranted consideration was the specified requirements of the tyre manufacturers.

These black and white points show clear differences between makes, but there is another overlay, which admittedly, falls into a grey area, and that is the one of operator fatigue.

It is obvious that a driver of a mechanical drive loader, who has to do more with controls — changing engine revs, changing gears etc is more subject to fatigue over a shift than one who is operating a loader with less functions to control and simply focuses on the functions of loading the bucket and dumping the load into the haul truck.

Another variable is down time for maintenance and repairs.

Three basic points were noted in this area of the assessment: (1) if an engine is running at a constant speed there is less maintenance; (2) if the loader design involves no transmission, no drop box, no differential there is less maintenance; and (3) environmentally, there is another plus. With less oils and filters to dispose of, the LeTourneau was shown to be more environmentally friendly.

And, the first two items point directly to less downtime (higher machine productivity) and lower maintenance / repair work (lower maintenance costs).

Clearly, a case exists for one of the makes, but more important, a way of delivering for your site, the dual benefits of cutting costs and lifting productivity, out there at the coal face.

One observer who has seen loaders at work at a wide cross section of mines, both in the Bowen Basin and elsewhere in Australia, made an interesting comment.

“Once your site acquires a LeTourneau, invariably another one, or more, follows.”

Usually, the process starts with someone deciding to depart from tradition … depart from conventional thinking and step outside the square.

Anyone who can introduce annual savings on operating costs and significantly boost productivity that run into so much money, has got to be delivering a great service for the company. And, it all can be done with the stroke of a pen.

*This article was written by Rod Lindblade for LeTourneau Technologies. For more information, call Rod at Northfield Communications – Business-to-Business advertising and journalism on 03 9681 9585, or email rod@northcom.net.au.

Technical enquiries

Lindsay Neven

General Manager

LeTourneau Technologies Australia

07 3902 9000

lneven@letourneau-aust.com

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