In order to improve the gradation and the quality of the filtering material, both sieved and blasted materials are used.And the quantity of gravel mined decreased.

• 根据料场砂砾石级配特点和反滤设计要求，综合利用筛分料和爆破料改善反滤料的级配，进而提高反滤料的质量，同时减少反滤料的开采量。