Quarry systems

Moscow is currently enjoying something of a housing boom. In 2004, some 8 million m² of residential floor space was added in the city, with many of the structures based on pre-fabricated concrete construction techniques. While these structural units tend to be manufactured locally, the high- quality aggregates required have to be sourced from as far as 1000 km away - one of the suppliers to the building boom is a quarry in Sortavala, located close to the Finnish border, in the Karelia region.

The raw material processed in Sortavala is a hard granite, the like of which is not available within 600 km of Moscow. But high quality aggregates are a &must' for the capital's pre-cast concrete industry, so stone of this quality has to be brought in by train or barge from distant Karelia.

Such a large transport distance obviously adds expense to the operation, so it is even more important than usual that the aggregate can be produced as cost-effectively as possible. The quarry in Sortavala is run by PIK Holding, one Moscow's largest construction companies, and it recently bought a Sandvik automated crushing plant for the Sortavala quarry, believed to be the most modern crushing plant in Russia.

The compact Sandvik design has enabled the new plant to fit in well on the existing site, meeting all the customer's requirements. PIK Holding replaced all the equipment in this project, with the exception of an existing railway loading system.

The plant consists of a primary crushing station with a Jawmaster JM1211 jaw crusher with a 1200 x 1100 mm feed opening and an E64 Rammer hydraulic hammer for breaking oversize boulders. The crushed material is conveyed to a Hydrocone H6800 crusher, as a secondary stage crusher, via an intermediate stockpile, while two Hydrocone H4800 cone crushers are responsible for the final shaping of the aggregates

The design of the plant allows quality adjustments of the crushed material according to current market demands, and the plant is fully computerised, so that one operator can control feeders, crushers, screens and belt conveyors.

The four screens are of the new Sandvik free-fall type, featuring screening decks with differing inclinations. This operating principle allows a small screen to process the same amount of material as a traditional screen twice the size.

The plant has a capacity of 430 to 475 tonnes/hour depending on operating mode. It was designed to maximise production of high quality 5-20 mm material for asphalt and concrete. But equally, the plant can be set to produce 5-10, 10-15 and 15-20 mm materials.

Efficient System

The Sortavala plant forms a complete Sandvik delivery, and was sold through their dealer in the region - Integra Ltd. Sandvik designed and built the control system. Each Hydrocone crusher has an ASR-system for fully automatic regulation of the setting in accordance with hydraulic pressure and motor load. The plant is dust encapsulated and almost dust-free thanks to modern point filters on crushers and screens. The equipment was manufactured in Sweden and France.

“Having run the plant for about half a year, we find it reliable and efficient”, said Mr. I. Boshakov, General Director of the Sortavala Crushing & Screening Plant Ltd. “Not only does the new plant cover PIK Holding's aggregate requirements, it covers several other customers' requirements as well. Well-coordinated supplies of wear and spare parts from stock held by the local dealer in Saint-Petersburg, the service group certified by Sandvik, and round-the-clock readiness to assist us, facilitate successful operating results.”

Production Increases

It is not uncommon for operators to find that production goes up dramatically when money is invested in the correct new pieces of equipment. This was certainly the case for PIK Holdings, which was aiming for lower costs, but found it created enough extra capacity to serve external customers.

On the other hand, some operators invest in new crushers for the primary reason of increasing capacity. Hanson Aggregates San Diego, part of Hanson Aggregates North America, had this in mind when it updated equipment at one of its facilities in the Carroll Canyon area of San Diego, California, US.

In an unusual arrangement, Sandvik Mining and Construction offered the company use of a new Hydrocone H7800 crusher - the first installed in the US - to test against the quarry's incumbent secondary crusher. Lined-up in parallel operation with the existing secondary crusher, the H7800 consistently outperformed its competitor, providing a production increase of up to 50 tonnes per hour. Considering the secondary crushers runs for 11 to 12 hours a day, that added up to a big production increase.

“Our goal basically was to see if we could get a higher production rate of finished product on the first pass through the crusher, without going through the circuit again,” said Ian Firth, area operations manager for Hanson Aggregates.

Service

There was another pleasant by-product of the crusher test, according to the plant managers - an excellent working relationship with their Sandvik Mining and Construction rock processing product group distributor, Aggregate Crusher Specialists of Corona, CA. Mike Murphy, owner of ACS, Inc., handles the equipment sales and applications, while operations specialist Don Markel, a long-time veteran of the crusher business, offers vital technical advice and quick service, according to Hanson's plant manager Jim Portlock.

“We get very good service and technical expertise as far as product knowledge and the ability to have detailed questions answered. Don is the first guy we call, and we always get straight-forward answers with technical depth. It makes a big difference,” added Mr Firth.

“That's great to hear,” Mr Markel replied to this vote of confidence. “I've enjoyed working here and I've become very familiar with this site and with the people. What we are trying to promote is annual machine audits, where we take the crusher apart and evaluate exactly where we are in its maintenance.” The programme seems to be working.

Big Picture

Investing in a new crusher is always a major decision for any business owner. Crushers do not operate as independent units, but are part of a production circuit made up of many links, so buying such a major piece of equipment requires careful consideration of the whole system.

The &crusher equation' has many components, such as the cost of purchase, training and installation versus the anticipated increased production and efficiency. And to be productive and efficient within a plant's overall capabilities, it doesn't make sense to buy too large or heavy-duty a crusher if it can't be fed the proper amount of material, or if it overproduces and creates bottlenecks in the downstream processes.

The Hanson Aggregates operators have been pleased with the Hydrocone H7800's performance for other reasons, namely its on-board automation systems, flexibility of operation and ease of maintenance.

“The automation surprised us with its ease of making changes in settings to make the machine more flexible in manufacturing different products,” said Mr Firth.

The Automatic Setting Regulation System (ASRi) crusher control system, available on all Hydrocone crushers, provides a continual flow of information to the operator and constantly makes adjustments for more efficient operation. For example, it adjusts crusher settings automatically in order to compensate for liner wear and helps ensure the highest possible crusher performance. Pressure and power in relation to load are automatically adjusted to suit the properties of the material and its moisture content.

In addition to increasing production, ASRi allows crusher operators to quickly determine if action is needed to prevent damage to the crusher and to avoid the resulting costly production slowdowns. The system is easy on the eyes of the operator, with simple color graphics (including presentations of cables and transducers), touch-screen interface and built-in instruction manual.

The Hydrocone H7800 also comes with the built-in TIMS™ (Tank Instrumentation Monitoring System) - a small and convenient control unit designed to monitor lubrication, temperature and oil flow. TIMS automatically watches all functions of the crusher, switching on cooling fans and heaters when necessary. It also provides enhanced control on the job site with a full factory guarantee.

In addition, the liners of the Hydrocone H7800 don't require any backing material such as plastic epoxy or zinc. This saves time mixing, pouring and waiting for the curing to take place, while increasing safety for the maintenance staff. •