The oil sands mining and extraction processes in Canada produce large volumes of tailings that are a mixture of mainly water, clay, sand, chemicals and bitumen. This mixture is transported to tailings ponds, where gravity segregation occurs. During this process, a stable suspension called mature fine tailings (MFT) is formed, which requires many years to fully consolidate. Therefore, land reclamation and water recirculation become significant environmental issues. For this reason, it is important to understand the tailings' content and their settling properties. This study uses the low-field nuclear magnetic resonance (NMR) technique to estimate the water, bitumen and solids composition of synthetic and real tailings samples through a bimodal compositional detection method under ambient conditions. NMR measurements were conducted in 15 minutes, which is a relatively fast measurement allowing for rapid monitoring of tailings compositions. The results show that the NMR technique can be a potential on-site fast measurement of composition and settling characteristics of tailings.