Hercules boosts production for Gallagher
The largest Hercules trommel screen in the world is currently helping to boost production at Gallagher Hermitage Quarry, near Maidstone in Kent. Designed and manufactured by Stelex Construction Equipment, the 1,000 tonnes/h trommel screen was installed in June last year to replace a smaller-capacity unit that was in need of upgrading.
Manufactured from high-grade round steel bars welded into support rings, the new 70-tonne Hercules barrel accepts a maximum feed size of 1.5m3 and is being used by Gallagher to remove fines from their as-dug Kentish Ragstone. This hard, fine-grained limestone is interbedded with layers of soft sandy material known as hassock, which the trommel separates out prior to primary crushing.
The 15.3m long x 2.3m (internal) diameter barrel comprises three 4m sections, two with 75mm apertures and one with 1,000mm apertures. The apertures are different to the earlier machine to suit a new washing plant; the –75mm goes to the washing plant for further processing, the –100mm +75mm goes to stockpile and the clean +100mm is fed to the primary crusher.
The unit is equipped with a 45-tonne capacity Hardox-lined feed hopper, which was specifically designed to fit the existing quarry layout. A variable-speed reciprocating tray feeder positioned beneath the hopper and supported on heavy-duty rollers ensures an optimum feed rate to match the quarry’s daily production target.
Both the feeder and screen are powered hydraulically by a diesel-driven power pack located alongside the unit. Drive to the barrel is via a low-maintenance and adjustable ‘live drive’ system with hydraulic motors through cast-steel support rollers.
Meanwhile, Stelex have recently launched the first of a range of fully mobile Hercules trommel screens capable of processing up to 500 tonnes/h. The first unit – a road-towable machine capable of handling lump stone sizes up to 900mm – is bound for a US customer in Missouri. The 45-tonne unit is fitted with a tri-axle and incorporates air-spring suspension, together with brakes and lighting that can be changed to suit either European or US regulations.
Stelex Construction Equipment Ltd, Prees Ind. Est., Prees, Whitchurch, Shropshire SY13 2DJ; tel: (01948) 840840; fax: (01948) 841147; email: [email protected]