초록
This study examined the actual conditions of quarries. aiming to offer preliminary data to help with restoration efforts of quarries after extracting rock material. The results are as follows. As for the current state of business, a classification of all sites surveyed showed the ratio of ceased operations: ongoing operations: quarries under restoration to be 58:5:37. Classified by the permit area, the ratio of the number of quarries with areas less than $20,000m^2$ (2ha) : between $20,000m^2$ (2ha) and $50,000m^2$ (5ha) : $50,000m^2$ (5ha) or more was 15:60:25. The classification by use of the rocks showed the ratio of construction aggregate (such as civil construction material) : building material : craft material to be 60:28:12. The ratio of quarrying methods of bench cut : slope quarry : vertical quarry wall is 40:18:42. It is indicated that 85% of all quarries surveyed are difficult to reclaim while 15% seem to be easier to restore. Among all surveyed, 34 sites were considered to be extremely difficult to restore. 17 of the 34 sites (50%) were quarry walls almost vertical that have been neglected after extraction. 16 of them (47%) were underground quarries that have left quarry walls deep under the ground. For the remaining 1 site, there doesn't seem to be any need for reclamation as it became totally flat after the extraction.