IT was a challenge to tax even the most brilliant of engineering minds; how to get rid of a 13m high tower of solid animal fat – and lift it safely over an electrical sub-station.

The conundrum of how to remove and dispose of the disintegrating 13 metre storage tank and the 29 tonnes of animal fat it had accumulated over 15 years, was a difficult one.

The tank had stood idle for more than ten years at pig and poultry feed-makers, ABN in Northallerton and over time the tonnes of fat had set into a hardened mass.

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The tank’s structural lifting devices had begun to degrade and it had to be hoisted over the site’s four-metre high sub-station.

Andy Sadler, operations manager at ABN Northallerton, said the tank was a major eyesore at the site.

The project was led by Ian Sullivan, regional manager of Lanes Group engineers' Teesside depot, who visited the site almost every week for a year to develop the plan.

The team put a heating coil through the top of the tank and pumped steam through coils already in the base to turn the fat into liquid. They then used a powerful vac tanker to suck up the liquid.

Tests then found the structure of the tank would not withstand lifting it away. Holes were cut in the top and bottom of the tank by using thin jets of cold water at extremely high pressures to cut through the metal.

Lifting chains were then attached and two cranes hoisted it away.

Mr Sullivan said: “After months of planning, we had a window of one day to carry out the lift. It was a bit of a nervous moment but it went perfectly."