An examination of factors affecting vegetation establishment at the Kitsault minesite

The end land use objective for most mines in British Columbia is a vegetation cover of equal productivity to that which existed prior to mining. The subject of this study was the Kitsault minesite in north coastal B.C.. The project had two components. The objective of the first was to identify plant and soil factors impeding forest development. Vigorous plant growth indicated that a number of materials and methods can be used to achieve a sustained vegetative cover on the wasterock dumps. Studies of similar natural substrates (recently exposed moraines in S.E. Alaska) showed that litter and N additions were the main driving forces for plant and soil development. The two plant species producing the highest amounts of litter and N on the wasterock dumps were Sitka alder and birdsfoot trefoil. While good plant growth was achieved on the dump benches, on the dump slopes it was impeded by the absence of soil-sized particles. The best source of such particles was the incompetent wasterock. The objective of the second part of the study was to evaluate the long term performance of the incompetent wasterock, used as a source of fines, on slopes at the angle of repose. The higher proportion of fine particles in the incompetent wasterock appeared to result from the relatively large proportion of sericite and calcite, most of which ended up in the < 2mm fraction. The modal composition of the incompetent wasterock coarse fragments was 90% quartz and K feldspar. The resilience of these minerals to weathering suggests that further fragmentation, beyond that observed in the first few years, will be limited, and thus the veneer of incompetent wasterock should maintain the angle of repose and maintain good drainage. With regards to nutrient availability, the incompetent wasterock appeared to be a better source of Ca, K, Mg, and P than any of the other wasterock types or the mineral layers in adjacent natural soils. Of the trace elements analysed, levels in the incompetent wasterock were no higher than in the other wasterock types.Land and Food Systems, Faculty ofGraduat