Log Handling - A History and Technology Update, 1992 Engineering Conference Proceedings

Log handling in North American mill yards is becoming more complex in order to keep up with the increased productivity of the Pulp and Paper Mills and changes of wood supply. Handling systems have undergone extensive revisions in the past 20 years and new ways had to be devised to solve specific problems.

The Railmounted "Portal Crane" is one such development. The Portal Crane travels over the load (or storage volume) and is not restricted where lift height is concerned. Portal Cranes then can handle highlifts required for gravity infeed chutes, can concentrate storage volumes in relatively small areas (increased storage heights), and reduce traffic volumes at any infeed deck due to its overhead approach. Railmounted Cranes of the Portal type have been used for 15 years and a consensus of Operating requirements has emerged. The typical Portal Crane Operator can be expected to make 25-30 picks per hour comfortably on a sustained basis, providing the Crane has the appropriate motion speed capability, and provided the travel distances are within certain boundaries. Load carrying capacities are primarily geared to Highway Truck loads .(usually 30 ton payload).

Load splitting is generally used for Off-Highway trucks with good success by only adequately experienced Operators, even for notoriously crooked species like aspen.

Whether a Portal Crane system is preferred over other handling systems depends on local conditions and choices should be made on broad economics, taking into account all costs.