香港海沙资源的勘探开发与管理

Exploration,exploitation and management of marine sand resources in Hong Kong of China

海沙开采已成为仅次于油气开采的世界第二重要海洋开采业。1980年代以来,香港政府投资1.7×108港元为寻找海岸围垦填料进行了一系列的海沙勘探活动,在1828km2香港水域发现22个地点海沙资源储量7.4×108m3,其中9个地点4.2×108m3储量因覆盖层较厚或污染严重或海区环境特别敏感等原因被暂时搁置。1990～2002年共开采海沙2.7×108m3,为形成2100hm2新土地的多项围垦工程提供了约一半的填料。基于地球物理勘探和钻探资料建立了香港海域第四纪层序和海沙产状地质模型,发现和证实了含气沉积物地震剖面的声波浑浊现象。香港政府对海沙资源进行统一勘探和统一管理,强调海沙开采的环境和生态影响评估,利用废弃的海床挖沙坑回填倾废的非污染海泥和受污染海泥。我国内地海沙勘探管理可以从中取得借鉴。

Exploitation of marine sand ranks today as the world second most important marine mining activity after oil extraction.Since the1980s,the Hong Kong Government spent about HK$170million and carried out a series of exploration activities of marine sand resources for coastal reclamation fill material.About 740×10 6 m 3 of marine sand in22sites were revealed in1828km 2 of Hong Kong waters,of which420×10 6 m 3 in9sites have been set aside by the Gov-ernment as their thick cover,seriously contaminated cover or environmentally too sensitive to dredge is suitable for exploration.From1990to the end of2002,about 270×10 6 m 3 of marine sand have been dredged from areas of seabed in Hong Kong to provide50%of the fill material for reclama tion,totaling2,100ha of new land.Based on data of marine geophysical investigation and marine drilling,Quaternary sequence stratigraphy and geological model of marine sand occur-rence in Hong Kong waters was established,acoustic turbidity on the seismic reflection profiles associated with Holocene marine sediments with gas was revealed and tested.The Hong Kong Government took the policy of unified exploration and unified management for marine sand re-sources,placed em phasis on environmental and ecological impact assessments for sand dredging,used exhausted marine sand borrow pits for disposal of uncontaminated mud and contaminated mud.All the above exploration achievements and management experience can be used for impor-tant reference of marine sand exploration and management in other places of China.