Browsing by Subject "Ground penetrating radar"

A promising Cu-Ni-PGE containing sulphide ore deposit was discovered in 2009 by Anglo American and since the company has continued studies aiming towards utilisation of the deposit. The discovered deposit lies underneath a Natura 2000 protected mire complex, Viiankiaapa, in Sodankylä municipality in Finnish Lapland. The research and exploration activities in the area are performed with mitigation and preventing actions in order to minimize the deterioration impact to the delicate ecosystem. The more detailed understanding of the hydrogeochemistry of the mire environment in its current state can assist: in monitoring, mitigating and preventing of potential environmental effects due to future mining operations as well as planning the monitoring program. Hydrogeochemical studies, consisting of water and peat sampling at eight sampling points, were carried out along a 1.6 km long study line. Water samples were collected from the surface of the mire as well as within the peat layer and the bottom of the peat layer. Water samples were collected using a mini-piezometer. The analyses for the water samples involved: major components, trace elements and δ18O & δ2H. Groundwater influence in the different sampling points as well as different sections of the peat was investigated using the mentioned chemical and isotopic properties. Peat sampling focused on finding samples which would have different hydraulic properties in order to find the influence of peat in the hydrology in the mire. Hydraulic conductivity of peat samples was determined using rigid wall permeameter test setup. The chemical and physical methods were supplemented by a ground penetrating radar survey completed with 30 and 100 MHz antennas. Studies of peat showed that the hydraulic conductivity varies substantially even inside the rather small study area. Widely recognized correlation between hydraulic conductivity and depth was not observed statistically, but the sampling sites individually show a clear connection with depth and hydraulic conductivity. The influence of the hydraulic properties of peat on to the flow of water in the mire was observed to be significant. In cases where the hydraulic conductivity of peat was very low, water flow may be prevented altogether. This was confirmed with the use of chemical analyses. With higher hydraulic conductivity, groundwater influence was seen more or less throughout the peat profile.