Aggregate supply in Hong Kong: past, present and looking to the future

Abstract

Hong Kong is one of the most densely developed and populated places on the planet, with a population density of just under 7000 people per km 2 and over 300 buildings with heights greater than 150 m, more than 90% of which used concrete as their main structural material. The nature and scale of this development means that aggregates from local hard rock quarries have formed an essential construction material for the development of the territory. However, the small area of Hong Kong (1104 km 2 ), its lack of readily developable land and increasing public concern on the impact of quarrying have led to the rehabilitation and closure of most local quarry sites over the last 20 years. The decline in local aggregate supply caused by this has resulted in an increasing reliance on aggregate imported from elsewhere, with associated implications in terms of supply, cost and quality control. Quarry closure has also reduced Hong Kong's readiness to process and reuse good-quality rock generated by construction projects. To combat these issues, a detailed review of the short- and long-term aggregate supply strategies for Hong Kong was conducted, including a territory-wide search for potential new quarry sites together with assessments of the feasibility of integrating other aggregate sources in the supply chain such as underground quarrying and the use of recycled aggregate.