Dam Safety: Monitoring of Tailings Dams and Safety Reviews

The awareness to tailings dam safety monitoring and reviews has increased by thecatastrophes resulting from failures of such dams worsened by increasing tailingswaste and construction of larger dams. The losses born by the mining industry fromhigh costs of compensations and environmental rehabilitation work have broughtthis matter into focus. In the present article the need for safety monitoring programsof tailings dam is highlighted and mode of failures and factors leading to them aredescribed. Basic principles of such programs are investigated with all phenomenaneeding observation described and their impacts explained. As in conventionaldams this work is carried out by visual inspections and use of similar methods andinstruments. In similar manners in both types of dams’ observation andmeasurements are done for measuring seepage water quantity and quality, phreaticsurface level and pore pressure and total earth pressure values in addition todeformation measurements; and all are done by similar devices and methods suchas weirs, piezometers, inclinometers, settlement plates and geodetic surveying.Basic differences between safety monitoring systems of the two types of dam,however, are presented in a tabular form. The continuity of safety monitoring oftailings dams is emphasized not only during the long construction phase but alsoafter that in the abandonment and closure phase which can last indefinitely in orderto watch for possible adverse effects on the environment and ecosystem due to thewinds eroding and carrying of poisonous tailings contents, in addition to contaminated seepage water entering surface water streams and ground water.Justifications for using real time monitoring systems for recording and transmittingall data to the control center are presented with emphasis given on savings in bothlabor and time and need for the discovery of warning signs enabling raising earlierthe alarm of possible failure or incident and the early taking of preventive measures.In this article it is argued that, in spite of the large investment of installing andrunning cost of comprehensive dam safety monitoring systems in tailings dams,such costs are justified as they form only a small percentage of the total investmentin the tailings facilities projects, and may save huge costs if failure does happen.Such systems may be considered as an additional insurance against such events.