Föroreningar orsakade av stenar inblandade i barrmassaved

Abstract: Holmen Skog AB is an important supplier of conifer pulpwood to the Iggesund Paperboard mill. After logging and transport to the landing by a forwarder, the wood is loaded on trucks for further transport, often by using separate loaders. During this handling process considerable amounts of stone material is sometimes mixed into the pulpwood and this causes problems for the industry. The aim of this study is to identify which part of the chain from forest to pulpmill, that contributes the most to this contamination. Sizes and total volumes of the contaminating stones were also investigated. Landings with stacks of wood were picked through by a forwarder to locate the individual stones. The same stacks were then run through the industry process and stones from the stone traps were registered. The result show that three quarters of the stone material could be related to the use of a separate loader at the landing while the forwarder contributed with the remaining one quarter. Each timber truck, with a load of 45 solid cubic meters under bark, brought on average 1.4 stones, sized over 12 cm, to the industry which is far from an acceptable level.