An overhaul of the pumping system at its main quarry has seen leading UK slate manufacturer Welsh Slate achieve a hat-trick of benefits through increased production and reductions in not only its operating costs but its impact on the environment.

The company’s largest quarry, Penrhyn at Bethesda near Bangor in North Wales, which Welsh Slate says is the largest single-site slate quarry in the world as well as the oldest (it dates back 400 years) complains of having a series of inefficient and expensive pump systems, the latest installed only just over a year ago.

Given that 85% of North Wales slate now comes from Penrhyn, Welsh Slate’s purchasing manager, Edward Griffiths, decided the situation needed sorting once and for all and enlisted the help of Nottingham-based Pioneer Pump Solutions.

His brief to Pioneer was to reduce the environmental impact of the pumping application by making it more efficient, reducing operating costs and increasing plant production – Welsh Slate produces 500,000 tonnes of usable slate annually for roofing, architectural materials, walling, rockery, paving and aggregate for gardening and construction.

The aim was to reduce pump downtime (breakdowns) and move more water because the company's operations often require more than 100 litres of water per second!

The existing system operated using two 2400 high head 90kW submersible pumps and two diesel generators mounted on pontoons with four 350m lengths of six and eight-inch hose, which often leaked. This had to carry the water 55m up and out of the quarry. The 90kW pumps were capable of pumping a maximum 50 litres per second each, giving a less than the ideal 100 litres per second.

Running at an average of 160 hours per week, which used more than 7,000 litres of fuel, the company was spending almost £250,000a year just on fuel for the pumps. In addition to this, the operation was producing almost 1million kg/CO₂.

Pioneer’s new scheme was to replace the two submersible pumps with one 150 clear liquid medium head 112kW diesel pump capable of moving at least 100 litres per second. It is mounted on a plastic pontoon with one fuel tank and 30m of 200mm wire-armoured hose. Pioneer also renovated the existing 150mm and 200mm hoses.

Even with a 68kW decrease in power, the new scheme reduces the weekly fuel consumption to 4,480 litres, and the annual fuel bill by 50%. At the same time, the operation’s carbon footprint is cut by 40%.

Pioneer’s system has saved Welsh Slate more than £120,000 a year in operating costs (fuel + rental rates) and 373tonnes of CO₂ emissions.

Production has increased due to faster de-watering (flows of 102 litres per second are now the norm and can increase to 140 if required) and pump breakdowns, which were accounting for a loss in production of approximately one day a month, have so far been reduced to zero.

Edward Griffiths said: “It did feel like we were sending men down there all the time to repair the system. Now it’s hassle free, fuel-efficient pumping.”

Pioneer’s general manager, Kieran Gagg, added: “When Welsh Slate contacted us we saw it as an exciting opportunity to do what most would see as an impossible task and we are delighted it has been so successful for them.”

Welsh Slate is used on worldwide projects as diverse as Buckingham Palace and Blackpool Tower, the Welsh Senedd, and heritage buildings in Australia and New Zealand.