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It is 100 metres tall and weighs more than six million tonnes. It is composed of coal ash and waste from the nearby power station, and it is still burning inside. “It’s not very pretty,” says Ines Llerena Gil, the town’s municipal architect. “But it has become part of our little town and we’re rather fond of it.” The ‘Terri’, as it is affectionately called, is a huge slagheap that has piled up over more than 100 years of open cast coal mining and electricity generation. It lies just outside the town of Puertollano, in central Spain. And since the country’s main high-speed railway line runs past it, more than 50,000 people see it everyday. It has become quite a landmark, one that everyone associates with Puertollano.

So when this small mining town received a grant from the central government to remove what most people would consider an ‘eye-sore’ there was much debate about what the town should do. “Everyone knows it and it is part of our identity,” says Llerena Gil. “We are an industrial town and there’s no hiding from that. We are proud of who we are.”

That’s when the town council had the idea of not levelling the mountain, but to landscape it into a beautiful park, high in the sky. The mission was to cut off the top, cover it with soil, plant grass and trees, and build a road up the side. Visitors could then take in the breath taking views of the surrounding countryside while sitting on one of the purpose-built terraces, or having a picnic on the grass. “It would be a way of preserving our coal mining identity, but without all the dust,” says Llerena Gil.

Cat machines mentioned in tender

“When we were asked to tender for the job,” says Tomás Omar, project manager, “we estimated that we would need to move about half a million tonnes of material to create the plateau, and we said in our tender that we would be using Cat machines – everyone knows

Caterpillar, it is a strong and successful company. So the fact that we would be using Cat machines could only help us win the two and a half year contract.”

The Terri (a word play on the Spanish word for sand) is now half way through its remarkable makeover. Electricity and water lines have been laid to supply the planned public lighting and refreshment kiosks, but since the Terri is still smouldering inside these needed special heat-resistant conduits. “We will be laying top soil and planting trees soon,” says Omar. “And importantly we will use local tree and plant species, because the whole project is really a celebration of Puertollano’s identity.”

The Spanish contractor, imes API, is using a Cat 330C excavator, a D6 track-type tractor, a M322D wheeled excavator, and a 140 motor grader to move and landscape this huge amount of earth. “We like Cat machines” says Alfredo Gonzalez, the motor grader operator. “I’ve been motor grading for eight years and I always love it when I use a Cat machine. They’re very comfortable and the visibility is great.”

Dust – the big enemy

“Obviously, you can’t move half a million tonnes of ash without creating dust clouds,” say Omar. “So to prevent dust clouds drifting over Puertollano we only work when the wind is in the other direction. At first we considered using special filters and air handling equipment for the Cat machines, but then decided that they were already robust and tough enough. And to date it has all gone according to plan.”

The local Caterpillar dealer, Barloworld AutoFinanz, is helping to keep the machines up and running. Its maintenance contract ensures regular service and inspection while its Scheduled Oil Sampling (or S•O•S for short) helps with predictive maintenance. Oil samples from each Cat machine are sent to the Cat laboratories every 25 days. “Most of the time the results come back with everything OK,” says Omar. “But occasionally the results identify a contamination problem, not surprisingly in such a dusty environment. Fortunately, these contaminations are rare and thanks to the S•O•S we always catch them well in advance before they causes any damage.”

The project was completed at the end of 2009. “But it really isn’t complete,” says Raphael Sanchez, Puertollano’s urban planner. “The park must be given time to grow and mature, this will definitely be an enjoyable experience, forus and for many generations to come.”