Concentrated industrial activity took place in this area from 1867 to 1961. Activities included smelting, refining, and manufacturing of materials including arsenical-based pesticides, refined gold, refined silver, cobalt metal, stellite, and machine parts. This is the most heavily contaminated part of the site. Most of the ongoing arsenic loading to the Moira River comes from this area, and the Mine Area.
Size of area: 25 ha
Contaminants of Concern: Calcium arsenate/arsenite, low-level radioactive materials, slag and gold mine tailings contaminated with arsenic, cobalt, copper, lead, mercury, nickel; and ferric arsenate (sludge from the Arsenic Treatment Plant).
Volume of Waste: Approximately 305,500 cubic metres (m3)
Consolidate and cover wastes with an engineered cover combined with groundwater and surface water flow diversion to enhance the existing collection/treatment system.
Consolidation of waste and capping
The most highly contaminated wastes will be placed in a waste consolidation area and capped with an engineered cover that is 1.5 metres thick. This will reduce the footprint of the wastes, and will isolate them from the environment.
The soil along the western bank of the Moira River, once the site of the arsenic baghouse, will be removed and placed under the engineered cap. The riverbank will be reconstructed with “clean” fill.
Less contaminated materials will be covered with an engineered clay cap 1.5 metres thick to isolate them from people and the environment.
Ground and surface water diversion
Groundwater and surface water flow will be diverted away from contaminated materials. Clean groundwater will be diverted away from the wastes and under the engineered cover by a passive groundwater interceptor well network located near the western boundary of the Industrial Area. Extensive grading and interceptor ditches will be built to drain or divert surface water from the engineered cover.
The existing groundwater collection/treatment system (the Arsenic Treatment Plant) will continue to operate.
Demolition of unsafe structures
Unsafe structures and tanks will be demolished and consolidated with existing ruins.