Major Wire Help Boost Limestone Production for Great Lakes Aggregates

07 March, 2016

First published in the February 2016 issue of Quarry Management as Screening Success

Installation of Flex-Mat 3 self-cleaning screen media from Major Wire helps boost limestone production for US quarry operator

Michigan-based Great Lakes Aggregates Inc. produce approximately 1 million tonnes of limestone annually at their Sylvania Minerals Quarry, in South Rockwood. Over the years, as the quarry increased the number of saleable materials produced on site, the operators encountered key screening challenges along the way, such as limited open area, screen breakage and severe blinding.

‘With only nine months of production time each year, it is important that we keep production on track,’ said Bill Begley, quarry manager at Sylvania Minerals.

The company’s goal at the quarry was to increase the throughput on two of its triple-deck wash screens while producing four different product sizes from clean, high-quality materials. After several failed attempts using other products to achieve these results, Mr Begley met up with Kevin Hinkley of Conveyall Industrial Supply Inc., and Brad Rice from Major Wire, both of whom had recommended that Great Lakes Aggregates to invest in the Flex-Mat 3 screen media.

Hindering production

All three decks of both screen boxes were originally fitted with modular polyurethane panels. The top deck had a 1/2in opening; the middle deck offered a 3/8in opening; and the bottom deck screen provided a 0.212in opening. The system worked fine as long as the load of base materials and washed products were split equally.

However, as Great Lakes Aggregates increased the amount of washed materials at Sylvania Minerals Quarry, the product quality diminished and lower production rates were recorded, as the screens needed a more open area.

To address the issues, the previous screen media provider suggested changing to its diamond-shaped (‘D’ style) wire openings and supplied urethane bucker bar covers for the flat deck rail bars on the screen boxes to create a crown for the side-tensioned panels.

The new panels were installed on the top and middle decks of both screening plants, but after running for only a few days the screening media panels broke apart, halting production for Great Lake Aggregates.

Screening solutions

As a result of the failure, the quarry operators decided to install Major Wire’s Flex-Mat 3 Series-D tensioned screen media and saw improved results. The diamond shaped media is suitable for use on many standard applications and for Great Lakes Aggregates, Flex-Mat 3’s wire technology was fitted on both the top and middle decks of a screen box.

On the company’s second screen box, for product comparison, the quarry team installed another set of the original ‘D’ style screen panels that were previously used on the top and middle decks. Once again, after just a few days of operation, the screen box with the original screen media broke while the service life of the Flex-Mat 3 product lasted almost four months.

Mr Begley commented: ‘We were really impressed with the wear life of Flex-Mat 3 and excited about the extra production. The other self-cleaning screen media we used didn’t have enough open area and didn’t screen as well as Major Wire’s product.’

Great Lakes Aggregates now use Flex-Mat 3 Series-D screening media on both of their triple-deck wash screen boxes at Sylvania Minerals Quarry. Production has increased from 39 tonnes/h to an impressive 80–85 tonnes/h, more than doubling the production of –1/2in x +3/8in limestone – a premium material used in asphalt. The manufacture of other washed products has also increased on site.

‘The durability of Flex-Mat 3 screen media has meant far less time performing maintenance duties and changing screens, saving valuable operating hours,’ said Mr Begley. ‘The plant can now run fewer hours and still produce more material on the ground. The only challenge now is that the tertiary crusher feeding the wash screens cannot feed material fast enough to keep up with the new Flex-Mat 3 screening media.’

Mr Begley added that he was not surprised by the performance of Flex-Mat 3, having experienced the screening media while working at one of Great Lakes Aggregates’ other quarries prior to Sylvania Minerals.

‘We were experiencing severe blinding; it was so bad that every 90 minutes the operation would shut down for 20–30 minutes to release the blinded material out of the screen,’ he said. ‘The quarry switched to Flex-Mat 3 screen media and since then has not had a problem with blinding.’

Another challenge faced by Great Lakes Aggregates was their overflowing settling ponds at Sylvania Minerals Quarry. The initial solution was to build another settling pond but the US$100,000 cost to develop one made exploring other options more appealing for the business.

Great Lakes Aggregates decided to invest in Major Wire’s HyperSlot screening media for a different area of the plant. The slotted screen media features unique alternating crimped and straight wires, which result in an uneven surface with one straight wire followed by one crimped wire. According to Major Wire, the crimped wire causes the material to slow down, giving it more time to pass over the openings resulting in better fines removal.

Since the installation of HyperSlot screening media on the bottom screen deck, quarry personnel have seen a 50% reduction in materials entering the settling ponds on site – down from 220 tonnes/h to 110 tonnes/h. Importantly, the change to HyperSlot has allowed the quarry to delay the development of an additional settling pond while providing another saleable product for the construction materials market.

For more information visit: www.majorwire.cc