Dig A Crusher Provides Money Spinner
- 16 December 2011
- Product News
A Rotar 900R screener bucket has helped a Nottingham-based company overcome a 17-year old materials processing problem, converting a tricky and sticky waste into a saleable commodity.
Nottingham-based North Midland Construction (NMC) is a rare find; a national civil engineering and building contractor that is a jack of all trades but appears to be a master of all of them. Operating as five individual divisions and subsidiaries, NMC undertakes construction projects covering water, power, utility, energy from waste, rail, road and civil projects, urban regeneration, environmental, and infrastructure work, and well as having its own mechanical, electrical and building companies.
Obviously there is a huge amount of waste material from its construction and utility work that needs to be processed and recycled as a result. Alongside the company's state-of-the-art headquarters, NMC has its own recycling centre, where construction and demolition waste can be separated, screened, processed, crushed, sorted and eventually reused.
However, because the majority of the geology in the Midlands has an overlaying cover of heavy clay, the processing of groundwork material has proved difficult as yard supervisor Kevin Morton explained. "We can remove stone and brick from the waste easily enough. We'll bring in a muncher to deal with rebar. We can screen and trommel the vast majority of the material whilst it is dry. But the moment it gets wet, the trommel blocks up and the screener simply isn't efficient enough to warrant trying to separate the waste," he says. "As a result it gets stockpiled until it's dry enough to process again. Except it rarely is. As a result we had a yard full of a highly sticky waste product we simply couldn't separate. As a result we accumulated a 7 metre high waste pile that was slowly enveloping the yard; one that the Environment Agency really took offence to. They refused to grant a further licence to hold more - although a different category - waste material, until we had found an answer to our existing waste stockpile problem."
Rotar to the Rescue
Help came in the form of a Rotar 900R rotating screener bucket from Middlewich-based Dig A Crusher that NMC saw in action at last year's Hillhead exhibition where one of the uses demonstrated by the rotating bucket was aggregate washing.
Suddenly realising they had stumbled on a possible solution to their muddy waste, a demonstration machine was soon on its way to NMC's Huthwaite yard. It proved so effective that it never left, and after a two week hire, it was purchased outright.
The bucket was fitted to an existing 21 tonne Komatsu excavator and work began in earnest. "The Rotar worked through the top layers of the stockpile quickly because it was fairly dry and uncompacted. We removed the top quarter of the stockpile, processed and washed it without problem. After this we had the most sticky mess left, which was more akin to thick mud with stones; a totally useless material that was destined for landfill. It had totally compacted through years of sitting in the rain," Morton continues. "But we stuck with the bucket but, because of the high wet fine content, we started to use it in a different way. We took to pre spinning the material before washing. This took out quite a bit of the fines. We then did a prewash, which took out the majority of the mud, before a final clean wash, this was simply to prevent having to constantly empty the skips that were used as the washing bays. The resulting material makes an excellent Type 1 product and we've since discovered that it also makes excellent clean drainage material, which the local farmers love, so we have yet another market for the aggregate."
Quality over Productivity
Kevin Morton readily admits that the system used to process this difficult material is not achieving high throughput levels but, he says, he is willing to forego productivity for the sake of quality and to finally tackle a 17-year old problem. "Although the way in which the bucket is used isn't going to win any production records, we now get two saleable products from rubbish. Topsoil can be separated in the wash programmes, allowed to drain in settle tanks and then used as clean backfill, whilst the real money-spinner, the clean aggregate can be recovered easily. We've opted for quality over speed and it's paid off," he concludes. "The original stockpile is now down to just a quarter of its original size. We have found the only machine capable of processing such a sticky product. Our operators love it for its ease of use, simple maintenance and the fact that we are stating to get our yard back. It is a brilliant solution to a problem that has plagued this yard for too long."
Dig A Crusher
Brooks Lane Industrial Estate
T: 01606 835544