Thus, backfilling of underground workings is
often regarded as best practice for the rehabilitation of mining voids (e.g.,
MEND, 1995). Such backfilled waste is often regarded to be as chemically
and physically secure as the original mined ore. In particular, the disposal
of tailings below the groundwater table reduces the amount of reactive
material that would be available for oxidation. Nevertheless, if the tailings
are stored above the groundwater table without a dry or wet cover,
oxidation may generate metal-rich acid leachate (Morin and Hutt, 1997).
The leachate in most cases will be transported in the saturated zone of
surficial aquifers where the prevailing groundwater flow will produce metal
and metalloid rich plumes down gradient from the mine workings (e.g.,
Warren et al., 1997; Younger, 2000). This study is based on seasonal
groundwater measurements and sampling and the results of kinetic leaching
experiments in combination with hydrological modelling. ”
System designs directly dispose of wastes as generated out of the sorting system as produced.
The B.C. MOM stop work order requires submission and approval of a waste management plan. The February 2013 technical report by Baldwin, now posted up at Banks Island’s website does not address or describe the specifics of the back fill/ separated waste materials.