Page 93 - HUB-4 Magazine Issue 86

Quarrying News
The existing bucket wheel solution was producing two grades of sand – coarse for concrete and fine for plaster.
The bucket wheel sand washing technology was old and inefficient, resulting in an average loss of 10% of saleable sand to the settling ponds. Moreover, the fine sand specification was not sufficient for asphalt production due to excessive fine material loss.
Due to the inefficiencies of the technology, these sands were very wet, requiring extended drying time. Additionally, the specification for the fine sand was inaccurate. Fine sand production was approximately 10 tonnes per hour.
The loss of fine material from the sand to the ponds led to rapid filling of the settling pond, requiring biweekly excavation. This involved stopping production during this time and incurred a significant additional cost of around $46,000 (€43,000) per year.
Given the limited available space near the existing plant structures and the site boundary fence, a compact plant design was deemed optimal for Harton’s Sand & Gravel.
The solution
Samples of the sand were taken from the site and it was determined that a SandmasterTM SP25 would be suitable for the application.
Flow sheet and budgetary offers were developed by the Weir Minerals team and presented to Harton’s Sand & Gravel.
The proposed solution was to bypass the fine sand processing on the bucket wheel and instead divert all this flow to the SandmasterTM SP25 compact sand plant. This would allow the cyclone to recover the fine material being lost to the pond and, at the same time, deliver sand that was dry enough for immediate use.
After some minor adjustments of the cyclone configuration, the plant is now producing asphalt grade sand in accordance with EN 13108-1: 2006.
The SandmasterTM SP25 solution included a Warman® WGR pump, Cavex® hydrocyclone, Enduron® dewatering screen and Linatex® hose and rubber lining. This particular SP25 also included our GemexTM belt tensioning system, ensuring the best possible efficiency in the pump drive, saving energy and increasing the wear life of the belt transmission. The solution was fitted with the GemexTM 160/180 belt tensioning system, delivering significant motor drive wear reduction and energy saving up to 7%.
The results
After a second opportunity to view the SandmasterTM SP25 in April 2023 the customer placed an order for the solution. This marked the first sale of a SandmasterTM machine on the island of Ireland. Having the machine available as stock for a quick delivery was a significant factor.
The recovery of the fine material, previously being lost to the settling pond, meant that instead of cleaning out the pond every two weeks, the pond has not needed excavation since the SP25 was commissioned at the end of June 2023.
This has resulted in two additional days of production at the plant and approximately 240 additional tonnes of fine sand produced every month. Fine sand sells for approximately $16 (€15) per tonne, translating to approximately $3,903 (€3,600) additional revenue per month, along with significant cost savings on pond maintenance in the region of $65,000 (€60,000) per year. This additional revenue of approximately $46,000 (€43,000) per year and cost savings of approximately $65,000 (€60,000) per year contribute to an ROI of around 6.5 months.
Bríain Harton - owner of Harton’s Sand & Gravel, said: “Brilliant machine, working even better than we expected.”
www.hub-4.com May/June - Issue 86
| p93 |