Owen Pugh Scores as Sandvik Takes the Corners

A North East of England company is using a Sandvik hydraulic breaker to extract vital minerals from a quarry that is approaching the end of its long and productive life. Carrying out primary breaking duties, the Sandvik BR 4099 is allowing Owen Pugh Aggregates to work sections of the quarry that had previously been inaccessible.

With its sea views, cliff-top walks and picturesque lighthouse, Whitburn in South Tyneside is not, perhaps, the first place you would expect to find an innovative quarry and mineral extraction operation.   But just a few metres from the quaint holiday destination enjoyed by many in the North East of England, quarry operator Owen Pugh Aggregates is extracting the last vestiges of value from Marsden Quarry, a 54-metre deep pit that has been supplying magnesium and calcium lime to the local area and export markets for more than 150 years.

Heritage & History
The Grade II-listed lime kilns and neatly landscaped entrance to Marsden Quarry are an early indication of the heritage and longevity of a site that can trace its magnesium limestone extraction history back to the mid 1800s.   Today, the 12-hectare quarry produces in the region of 150,000 tonnes/year of magnesium lime for agricultural applications in export markets including Belgium and Holland.   The site also produces around 40,000 of calcium lime for the domestic UK agricultural sector, along with around 120,000 tonnes/year of construction grade limestone for aggregates applications in civil engineering.

But with around seven years of reserves remaining, Marsden Quarry is rapidly approaching the end of its natural life, and operator Owen Pugh is turning its attention to some less accessible and previously unworked areas of the site.  
“Having exhausted most of the quarry’s primary reserves, we are now working the corners, and that takes us close to the old lime kilns and neighbouring houses to the South of the site,” explains general manager Andy Mountford.  
“We have, therefore, stopped blasting in these areas and we have had to find an extraction that causes considerably less vibration.”

Hard Rock
The low vibration solution came in the form of a 3,380 kg super silenced Sandvik BR 4099 hydraulic breaker that is allowing Owen Pugh Aggregates to work sections of the quarry that had been inaccessible to the drill and blast process..  Utilising a new operating principle, the breaker has been matched to both the application and to the 47 tonne Hitachi hydraulic excavator upon which it is mounted.   

The Sandvik breaker is used to break out the overlying calcium limestone, beds of which vary in thickness from 10 to 25 metres.
“The calcium limestone is extremely hard,” comments Owen Pugh’s business development manager, Philip White. “But we have equipped the BR 4099 with a limestone chisel and it makes light work of even the hardest rock.” The Sandvik BR 4099, which benefits from enhanced hydraulic efficiency for an exceptional power-to-weight ratio, utilises the VIDAT (Vibration Dampened Tierods) system to provide improved reliability and reduced downtime.   A state-of-the-art sealing system, enhanced lubrication and longer service periods also help reduce operating costs.

Mountford and White are clearly impressed by the low noise, low vibration characteristics of the Sandvik breaker.   But they are even more impressed by the productivity and cost savings they’re achieving by using the hammer in these inaccessible areas of the site. White asserts that the Sandvik unit is producing in excess of 700 tonnes of broken rock per day. With the overlying rock broken out, the breaker is then switched for a ripper tooth or bucket to extract the softer magnesium limestone beneath, maximising the utilisation of the Hitachi excavator.

“Even setting aside the vibration concerns, blasting in these corners of the quarry would have been slow, delicate and considerably less economical,” Andy Mountford concludes. “Obviously, primary breaking would not have been a viable option in the main parts of the site. But based on our calculations, I believe that the Sandvik breaker has reduced our extraction costs by as much as 50 percent in these difficult areas.”

www.miningandconstruction.sandvik.com