Seasonal freezing and thawing can have
significant effects on tailings management. Tailings delivery, depositional
schemes and water treatment are examples of activities that must be dealt with
extra concern in sub-zero temperatures. Changes in mechanical properties,
drainage possibilities or embedded frozen tailings layers are effects that can
arise in poorly managed facilities. To avoid such consequences, a good
understanding of the seasonal effects on the tailings deposit is needed. To get
a better understanding of the geothermal regime in tailings, this paper
presents a case study with geothermal modelling performed for the Laiva
tailings facility in Finland, where major seasonal freezing and thawing periods
are present. Ground temperatures and frost lines were predicted via
one-dimensional modelling using air temperatures and snow cover depths from
adjacent weather stations, and basic soil properties from the facility.
Simulated results were compared to data obtained from thermal instruments in
the field. The snow cover and its estimated thermal properties were shown to
have large influence on the results. The model was able to accurately predict
the thermal regime measured in the field. Strong agreement was shown, both in
terms of ground temperatures and frost front positions. The methodology presented is useful for
tailings management schemes in cold regions.
Keywords: Geothermal Monitoring,
Geothermal Modelling, Tailings, Soil Temperature, Frost Tubes, Snow Cover.