The Cobalt Options Project - Rehabilitation of an Old Silver Mining Town in Northeastern Ontario, Canada

Abstract

In June 1987, Highway llB collapsed into abandoned mine workings at the entrance to the Town of Cobalt. Although subsidence problems were not unknown to the town, this cave-in managed to cut off access to three communities and gained widespread attention of the media, government bfficials and politicians. Geotechnical investigation revealed a network of shallow unmapped mine workings beneath the highway. The possibility of sinlilar shallow workings occurring elsewhere beneath the town had to be considered.Mounting concern for public safety led some officials to believe that the town ought to be abandoned and this led to the establishment of the Cobalt Options Project in 1988. Four options were developed by a multi-agency provincial government committee: 1) maintain 2) buy-out 3) relocate 4) maintain and investigate, repair, relocate or buy-out An abandoned mines inventory of the town was prepared as part of the Cobalt Options Project A . total of 17 areas designated for "caution status" were identified. This information, when combined with the geology of the area, influenced the committee to recommend option four. This option was accepted by the Government of Ontario. A prioritised testing and remedial work program was initiated in the spring of 1989 and is expected to be completed by 1993.