Conveyor upgrade at Tarmac’s Blashford Quarry

Tarmac has upgraded the 2.5 km conveyor at Blashford Quarry system to harmonise the drives on the 14 conveyors and to increase the handling capacity from 150 to 350 tph, with the additional benefits of improved reliability and reduced maintenance costs.

Operated by Tarmac South West, Blashford Quarry is located near Ringwood, New Forest, Hampshire and contains a substantial sand and gravel deposit with an underlying reserve of sand. The current processing plant comprises a barrel washer, sizing screens and open crushing circuit, which is due for replacement in 2008.

Processed material is used in local Tarmac concrete plants and is also supplied to builder's merchants and local contractors operating in the Ringwood and Bournemouth area.

Canning Conveyor was involved in the project that saw a staged upgrade of the conveyor system, which commenced in January 2006 by extending the conveyor system at the face with a new 120 m long x 750 mm wide field conveyor.

Canning Conveyor then split an existing C4 conveyor and interfaced a new 20 m long elevated lattice section with walkway. This included an electrically operated two-way chute at the end of this conveyor (new C4a); through which can be either fed gravel onto C4b to existing plant, or sand onto the two conveyors. This new section is powered by a ceramic lagged SuperDrive motorised drive drum, including Rulmeca jib discharge and high and low tension drums and included the installation of a polyurethane primary and a tungsten blade secondary belt scraper.

This was followed by the modification of an existing C4 horizontal conveyor, which entailed a new 22 m long x 750 mm wide elevated transfer conveyor complete with a tail end loading section to make C4b. Driven by a 22Kw Canning SuperDrive motorised drive drum this is fitted with primary and secondary belt scrapers and emergency stop, pull wire system.

Canning then completed this section into the plant with the supply of a new 22 m long troughed belt radial stockpile conveyor. Complete with walkway assembly and three sided head platform this radial conveyor is of lattice frame construction and is designed to accept up to 250 tph from the feed conveyor C4a. Powered by a ceramic lagged 22 kW SuperDrive drum the radial conveyor elevates at approximately 16° before discharging to a 5 m high stockpile.

The third stage involved a complete retro-fit of all Canning SuperDrive units to the existing conveyor system; ten ceramic lagged Canning SuperDrive motorized drive drums were supplied along with replacement jib discharge, and high and low tension bend drums. Conveyor C9 was the recipient of two 22 kW double SuperDrive units due to the length of the conveyor and previous problems with belt slipping. New belt scrapers were supplied throughout the system as necessary, along with new heavy duty mesh guards where appropriate.

In a fourth and final stage Canning supplied 34 non-drive drums to complete the upgrade as the existing non-drive drums would not capable of handling the upgrade to the system.

Some general refurbishment was also completed by Canning, in particular modifications to an existing blending plant which included greedy boards to three sides, full length walkway, access stairs, hoppers support structure and ancillaries.

Throughout the project Canning Conveyor were responsible for the design, manufacture and installation throughout all stages.

Gordon Tuck, area operations manager, comments: "The team at Blashford worked extremely closely with Canning Conveyor on this phased upgrade project. We are delighted with the immediate benefits, and are confident that Blashford will enjoy significant energy efficiency, quality and reliability improvements going forward"

With completion of the whole system Tarmac will be well positioned to continue successful operations into the near future.

Author JVMS Ltd