256 Land, Public Works and Utilities
During the year, the department continued to produce geotechnical guidance documents to disseminate new technological development findings and improved design and construction practices. In particular, Technical Guidance Notes giving enhanced geotechnical guidance on design and quality control of slope works were promulgated.
The Geotechnical Information Unit in the Civil Engineering Library, which houses the largest collection of geotechnical data in Hong Kong, served more than 26 000 public users during 2004.
The department provides specialist geotechnical services
geotechnical services to government departments, including the provision of ad hoc geotechnical advice and the conduct of feasibility studies, detailed investigations, design and construction supervision for a wide range of public works projects. The projects handled by the department during the year included site formation works at Kong Sin Wan Tsuen, Pok Fu Lam, North Point Salt Water Service Reservoir, Quarry Bay Salt Water Service Reservoir, Yau Tong No. 2 Freshwater Service Reservoir and Magazine Gap Road No. 3 Freshwater Service Reservoir Extension; and geotechnical works for the drainage project at San Tin and Stage III of the Shenzhen River Regulation Project. In addition, the department provides construction material testing and ground investigation services to support public works projects. The testing service is provided by the Public Works Laboratories. During the year, some 910 000 tests were carried out and 12 500 metres of soil and rock drilled.
Mining and Quarrying
The department enforces legislation relating to mining, quarrying and explosives, and administers quarrying contracts. It processes applications for the manufacture, storage, conveyance and use of explosives, and inspects stone quarries, blasting sites and explosives stores.
Hong Kong consumed 13.5 million tonnes of aggregates and other rock products in 2004. About 50 per cent of its demand for aggregates and rock products was met locally, with the balance imported from the Mainland.
One quarrying contract and two quarry rehabilitation contracts were in force during the year. The rehabilitation contracts require the operators to rehabilitate the quarries within a specified period, in return for the granting of rights to process and sell surplus rock excavated during the course of the works. The rehabilitation works involve recontouring and extensive planting to blend the quarries with the surrounding hillsides.
The department manages two government explosives depots (one at Kau Shat Wan on Lantau Island and the other at Piper's Hill, Sha Tin) which provide bulk storage facilities for imported explosives. It also undertakes the delivery of explosives from the depots to blasting sites and issues shot-firer certificates. About 2 200 tonnes of explosives were consumed in 2004, used mostly for quarrying and site formation works.