|Lafarge Aggregates choose Sandvik Hydrocone|
Lafarge Aggregates’ Dry Rigg Quarry near Settle in North Yorkshire has been quarrying and processing high quality greywacke mineral (locally referred to as ‘gritstone’) for more than 40 years. The quarry supplies high PSV chippings to sites and depots as far afield as Hampshire and Edinburgh. Material has even been supplied to the Falkland Islands for resurfacing the airfield runway!
During the winter of 2004/2005 Lafarge entered into discussions with various crusher manufacturers to upgrade the old tertiary section of the existing plant, with the objective of increasing the quality and yield of key products. Sandvik, with the aid of their advanced Plant Designer simulation software were able to simulate both the existing plant and proposed development, aiding Lafarge in their evaluation of the viability of the project. This tool proved to be invaluable, not only in the assessment of the final solution, but also for assessment of alternatives that were disregarded.
Sandvik eventually secured the order with a solution that involved the replacement of two existing 3’ Shorthead machines with one Sandvik H4800 Hydrocone, fitted with the Sandvik ASRi control system. The proposed solution was implemented in the spring of 2005, with local engineering contractor Gissing & Lonsdale being employed to install the H4800. Installation on the foundations of the old 3’ machine was swift due to the use of a transitional frame, manufactured by Gissing & Lonsdale being employed to support the normal Sandvik floating frame that incorporates both the crusher and drive motor.
The Sandvik ASRi control system is without doubt the most sophisticated crusher control system on the market today and has played a major part in the production improvements experienced at Dry Rigg. The ASRi is able to operate in conjunction with all Hydrocone crushers, and is the latest generation of computer control system that monitors simultaneously the crusher power draw, Hydroset pressure and position of the main shaft. All these parameters, together program selection, calibration and review of current and historical data are stored and displayed on a remote display with “touch sensitive” screen, mounted in the control cabin. The plant operator is now able to monitor, adjust under full operating load without stopping the crusher feed, change crushing programs and calibrate the crusher without leaving the control room. This has proved to be an additional benefit both in terms of productivity and health and safety of the operators.
Sandvik are continually developing crushing chambers to maximise the yield of key fractions. This has led to the selection of the chamber employed at Dry Rigg, resulting in a significant increase in 10mm production. This can be seen on the attached graph, demonstrating the steep gradation of the curve, maximising the yield of 10x6mm product.
Installation, operation and increase in quality and yield of key products have proven to be very successful, with yields increasing by +25%. However, Lafarge have a rigorous policy of carrying out an audit of all capital projects to ensure the investment is not only performing, but is producing the return on investment originally predicted. Lafarge are pleased to admit that the KPI (Key Performance Indicator) for Dry Rigg Quarry has seen a substantial improvement, solely attributable to the H4800 since its installation.
Bill Craggs, Lafarge Cluster Production Manager for the North West said: “The H4800 has not only met all the criteria that was predicted, it has exceeded them!”