Quarrying a new site entrance

Gallagher Ltd is Kent’s premier building, civil engineering, quarrying and property business, with a reputation for doing things professionally and getting the job done. The Gallagher Group started in 1973 and is based in Kent, England. The business started out as a grounds work contractor and has since established into a main contractor and principle contractor, offering the best in civil engineering, property development, design and build contracting and quarrying.

Gallagher has a long standing partnership with Leica Geosystems Ltd, having successfully used Leica Robotic solutions since the TPS1100 model range. In June 2015 when Leica Geosystems launched the new Captivate range, Gallagher was keen to invest in all the advantages of this new technology. To date, Gallagher is now equipped with 17 Captivate one person kits and a GNSS unit, showing their loyalty and trust to the Leica Geosystems brand. They were keen to put them into use.

Gallagher was approached by their customer J and J Franks Ltd to work on the Mercers South Quarry on the Old Reigate Road in Betchworth, Surrey. They were awarded the contract for the construction of a new site entrance to the quarry and works were undertaken over a two month period. A diversion was set up to allow pedestrians and motorists to access the villages either side of the access way. The new access way was fundamental to J & J Franks, allowing it to continue operating its quarry activities and providing continued employment for its skilled workforce.

Leica Captivate software was used for the project to help reduce any unnecessary costs and delays associated with complex projects and were fundamental to the setting out of the project.

The initial stages of the project were for Gallagher to construct a cut and cover tunnel in order to form the site entrance. To do this, it was first necessary to check for existing statutory services (BT, UKPN –LV + HV and gas) such as water, gas and telephone lines which added to the challenges of the job. Trial holes had to be made in order to check the depth of the site, making sure the site entrance was deep enough to put in the bell mouth (site entrance). Using Leica Captivate solutions meant better measurement accuracy, providing even the smallest of details, quickly and easily. Leica Geosystems’ products and solutions were used in order to complete the project in budget and on time.

When setting out on this project, positional accuracy was paramount, it was crucial to understand exactly where the new works might clash with any statutory services so as not to cause any unnecessary disruption. The Leica Viva TS16 and Leica Viva GS14 were chosen for this, with the Leica Viva GS14 also being used for the basic cut and fill operations at the start of the project. The Leica Viva GS14 was perfect for this scenario, as it is purposefully made for demanding environments such as quarries site entrances and it provides real endurance in extreme temperatures and weather conditions. Robust and lightweight, it made it easy to transport around the quarry site. Simple, accurate and easy to use, the Leica Viva GS14 was partnered with the new CS35 Tablet which ran the Captivate software and was connected to SmartNet for accurate GNSS RTK corrections.

The Leica Viva TS16 ‘self learning’ one person total station was chosen because of its versatility to adapt to any environmental condition, boding well for a quarry site. Running the Leica Captivate onboard software, the most comprehensive onboard capability available, the exact conditions of the quarry site could be surveyed and recorded. This provided an understanding of any potential clashes or pinch points with the utilities. The Leica Captivate software allows for a really great user experience.

Using this survey data from Captivate, a 3D model was produced of the site and the design was determined for the new work. The survey data helped Gallager to decide on the best alignment of the road, making sure that the existing contours of the field were followed. Then with the new design and services, data was loaded onto the Leica CS35 tablet and available on site in the 3D environment within Captivate. All elements of the site could be staked out with a ‘live’ understanding of any potential clashes or pinch points with the utilities.

Completing a complex construction project like this one at Mercers South Quarry wasn’t without its challenges. Making sure the existing statutory services were deep enough not to be damaged was imperative to the project. The Captivate kit from Leica Geosystems made sure the setting out and allocation of these services was quick and easy. Without the surveying equipment from Leica Geosystems and if the services were damaged in any way, it could have set the project back six months or more. Other obstacles included a footpath which was in the way and needed to be removed. Trees and shrubbery also needed to be cut down surrounding the quarry with minimum disruption to local pedestrians and residents. The contract was completed within tight time constraints to minimise the disruption to local pedestrians and motorists.

The project started in July 2015 and the first part of the road was completed in January 2016. Once the quarry has been filled with sand and landfill, Gallagher will be returning the quarry site to complete the access road to the permanent quarry office area. It will then be a completely new working quarry with a new access roads and new entrance site. The newly functioning quarry will benefit the whole community and provide vital new opportunities to the area.

The Leica CS35 tablets offer them so much more than a conventional total station controller, being a full Windows 8.1 Computer, the capabilities it offers for onsite use are almost limitless. Gallagher has already installed AutoCad and their regular IT services onboard. The Leica CS35 tablets can be used for everything from setting out and surveying, to filling in check sheets, documenting and photographing as-builts, exchanging important data and doing email.

"We wouldn’t have been able to complete this construction project for J and J Franks without the excellent kit and solutions from Leica Geosystems”, remarks Ken Maillinson, Technical Contracts Manager at Gallagher. “We always choose Leica Geosystems solutions for our surveying jobs as we can rely on the high quality of the instrument and the accuracy of the measurements. Furthermore the support and excellent after care received from their Technical Support and Technical Service teams are second to none”.