PJ Thory Ltd invest in a new AggReclaim System supplied by Molson Washing.

Established in 1965, Peterborough based PJ Thory Ltd have grown and developed into the region's largest supplier to the construction, agricultural and commercial industries. They supply several diverse products including a vast range of gravels and shingles, sands, granites & limestones including single sizes and certificated subbases. They also offer recycled materials to Type One & 6F2 specification from their wide range of quarries and recycling yards which allows them to supply materials at competitive rates.

At their PJ Thory Peterborough Quarry operation, they have operated a wash plant for the last seven years. As demand has risen, they have found themselves unable to satisfy this ever-increasing demand and with no ability to extend their lagoons they were unable to support the addition of another standard washing plant.

With a solution needed to service a new contract an introduction by Molson Washing to the new AggReclaim system left them with no hesitation to invest in this innovative system.

This new system has not only increased and supplemented the production of sand and gravel for PJ Thory but has made a significant reduction of water usage throughout the process.

“Having seen the new AggReclaim at the recent Molson V.I.P event I was keen to see the machine in a working environment, so I met John Dunne on-site to describe the operation,” said HUB-4 Editor John Edwards.

John Dunne - MD of Molson Washing, takes up the story, “Traditionally wash plants pump sand to cyclones which require significant amounts of water to pump sand to keep it moving through the pipes.

“The AggReclaim System we have brought to the market hasn’t got a separate ‘stand-alone’ sand system because it’s incorporated within the specially designed and patented screen box. Where we are moving material, we are putting in an ‘all-in’ feed ranging from -50 to 0, with anything that floats being scraped out backwards at the rear of the machine. Everything else then moves forward in water; with the water, sand, and silt moved forward mechanically by the 8-metre-long scrubber with the very heavy-duty paddles producing an aggressive attrition.

“With all the material hitting the top screen, the -50/+4mm stone is cleaned and taken off and graded into a 3-way split of 40/20/10mm. What goes through the screen is the water and all the sand and silt onto the bottom deck which is configured as an uphill dewatering screen. This is fitted with a 0.3mm mesh which allows 90% of the sand to be captured on the screen with the water flowing backwards. However, the underflow from that screen still contains 300/150/75µm therefore this is all pumped back onto the top of the bed of sand, or into a small cyclone cluster, resulting in a concrete specification sand and clean stone with the silt going back to the pond.”

Significant water savings:
Designed to operate at up to 70tph, the AggReclaim system uses approximately 1 cm metre of water per ton of input material against a standard wash plant moving 3.5 cu metre of water per ton of input material simply because it is required to move sand along pipes in contrast to the mechanical operation and the use of gravity of the Agg Reclaim system.

John, continued, “We have also designed a super fines cluster of cyclones that we can fit for clients doing remediation work who desire a cut down to 30/40µm.”

Processing ability:
Although the AggReclaim is processing natural sand and gravel for PJ Thory it will also produce the same results whether it is scalpings, crushed dust, soil washing or anything that has sand and gravel in it or stone and fines.

John, added,” We have a prototype in Wales processing crushed dust and when the unit at PJ Thory Peterborough Quarry has finished its current production increase it will then move to another PJ Thory recycling site in Peterborough where is will be it will be tasked with recycled soil washing.

“It occupies a small footprint, and it is easy to install, taking around 2 days and should not require specific planning as it is classed as a flotation unit. Basically, it is a remarkably simple method of producing saleable in-specification sand and washed aggregate. In essence the entire system relies on the finite settings and a specific of resonance within the screen box together with other special settings throughout the system.”