Long term in-situ behaviour of oil sands fine tailings in Suncor’s Pond 1A

Abstract

Suncor Energy Inc’s oil sands operation north of Fo rt McMurray, Alberta, has been in production since 1966. Pond 1A, a fluid fine tailings (FFT) storage and fl ow-through recycle water pond, began infilling in t he 1970’s. The first sampling programme of the FFT was conducted in 1977, with periodic follow-up programmes through to 2010. This pond has been used to store volumes of FFT in the form of Mature Fine Tailings (MFT) at significant depths in relatively undisturbed condit ions for over 25 years. This site, unique in the i ndustry, is important to understanding the long-term behaviour of fluid fine tailings in the oil sands landscapes. The observed behaviour provides insights into potential storage and material strength gain projections. S everal decades worth of sample profiles are provided, alon g with general observations on the potential implic ations to the industry. Pond History Pond Construction Suncor’s oil sands site, situated in north-eastern Alberta near the city of Fort McMurray, began operations in the mid 1960’s. Immediately west of Pond 1, the first tailings pond in the oil sands no w known as Wapisiw Lookout, was one of the first open pit mining areas on the site. Once mining was completed the pit was converted to a fluid storage pond in 1976, with transfers of Mature Fine Tailing s (MFT) and water from Pond 1. The pond bottom remains primarily in-situ ground with what is assumed to be very low permeabilities. The pond was filled to capacity over the following three years , with dyke construction consisting of hydraulically placed tailings sand in areas to the south and east of the pond. Pond Operations