South-East Qld Underroad Drillers was contracted to install three case bores under Queensland Rail lines at the Port of Gladstone for water supply to the coal loading facility. These bores ranged in distance from twelve metres up to thirty metres. The initial bore was for 600 diameter steel pipe into which 450 diameter class four concrete pipes were later installed.

The ground conditions were that of fill on top of marine mud. The soft ground conditions proved challenging and presented stability issues in regards to machine support and steel casing support. This support was further compromised by wet weather conditions at the commencement of the project. It was decided that concrete slabs would be poured in an effort to support machinery along with the importation and use of a railway ballast.

Despite ground support issues and wet weather, obstacles were overcome and the bores and installation of recycled water mains were completely successful.

SEQUD have been employed to assist in the relocation of water mains and rising sewer mains, for the expansion of the rail corridor from Caboolture to Beerburrum. It was requested we case bore holes for this relocation. Steel casing from 300mm diameter up to 500mm diameter was bored and installed over lengths ranging from 24 to 48 metres each. Invert levels reached up to 4.5 metres deep on occasions.

Ground conditions were found to be quite agreeable, ranging from clayey sand to straight sand. Heavy ground water was encountered on two of the drills however this did not pose any major problems. Site safety has been of the utmost importance throughout this job with constant inspections.

This project is in its late stages with an expected completion of 31 October 2007 if not before.

SEQUD were approached to install a 160mm diameter sewer on 1.4% grade from the basement of a building through to a manhole outside. We used our McLaughlan Petrol 20B Auger Borer to complete these works.

We encountered a number of problems before the commencement of works. These were that the invert level was over four metres above the basements ground level, and that we have to drill through the manhole wall and access in the building was very restrictive. Safety now became the most pressing concern. To combat these problems we had a working platform built and engineered to take the maximum load of the auger borer. Along with this a specialty fall arrest system was acquired for the two man crew to work in. Lighting was also a problem, but was easily overcome by the use of lighting towers.

Once drilling had commenced, the ground conditions encountered were far better than expected, being a dry fill material not the expected marine mud. We attempted to drill through to the manhole but were unsuccessful and had to use a small air hammer drill to mark the centre of the bore and jackhammer the remaining concrete from inside the manhole. The 160mm product pipe was then installed and the remaining void was then grout filled.

In all the job was a success and both the drilling crew and the customer were happy with the efforts and the end result.

SEQUD were approached regarding the installation of a 150mm PVC pipe for sewer on line and grade at Palm Beach on the Gold Coast. We used our Soltau RVS80 machine to ensure the line and grade of the sewer were absolutely correct. This project was a test of customer and resident relations as it had been running for eighteen months prior to our works. As a result residents were already on tender hooks.

Upon project commencement several problems were immediately realised. The first problem encountered was that of the water table. The sewer line was required at five metres deep, but the water table was 1.5 metres below the ground level. Ground conditions were wet sand down to 3.5 metres deep then flowing sand from then on. Due to the ground conditions dewatering methods were restructured to ensure that the flow of the sand was kept in check. Along with this restructure foam injections were used to help with stemming this flow.

Access to reception pit was also posed a problem as it was located in one of the residents backyard. In order to get all our machinery to the reception pit a 100 tonne crane was required to lift the machinery over the house. Additional problems were encountered and overcome throughout the project such as flowing sewerage.

Despite the unusual conditions SEQUD ensured that both the customer and the residents remained happy at all times. Congratulations are in order for all involved in this project for their constant perseverance and the fantastic final result.