On the use of sand washing slimes for waste containment

摘要

Sand mining has long been practiced in the southeast sand belt of Melbourne to obtain clean sand for use in construction.The material remaining after the snad extraction,which generally exists in a sludge or slurry form,is commonly referred to as slimes.Since the late 1960s most of hte abandoned sand mining pits have been used for waste disposal.Due to the unique hydrogeology of the region,the use of slime cut-off walls has become an essential consideration in the design of waste containmetn facilities in abandoned sand mining pits.One technique to isolate the landfills from adjoiing shallow aquifers is to construct cut-off walls using hydraulically placed slimes from sand mining (fines washed from the sand).This involves placing wet sand washing slimes mixed with clean fill to achieve a low permeability slurry curtain around the landfill walls.Another alternative successfully used is the use of a sidewall liner in which there is a combination of compacted refuse bales and slimes.This paper presents and discusses various facets linked to this innovative method for using slimes in waste containment systems.