Interpret Alignment Patterns

The pattern of the alignments generated by an unseeded optimization can reveal much about potential corridors. The alignments in the following figure are divided into three main groups. The two main groups of alignments pass through the small mountain range to the northeast and then spread out through the flat regions of the study area. They then climb through the major mountain range to the finish point converging on three main corridors.

A third corridor has been identified north of the start point to avoid the majority of the small mountain regions to the northeast. These alignments spread out across the plain and then rejoin the three main groups of alignments as they climb the major mountain range to the end point. The cost of the alignment passing through this corridor is still reasonable.

This indicates that:

• the area north of the start point should be investigated further with more analysis.

• there is more scope for movement as the alignment passes through the plain

• there are three main corridors for investigation as the alignment climbs the major mountain region to the finish point. The alignments through the mountains follow a very clearly defined corridor indicating that there is little room to move within the mountainous regions without significantly increasing the overall alignment costs.

Inspection of the alignment cost shows that it rises from $53 million for the cheapest to $96 million for the 22nd cheapest and then jumps to more than $20 million in additional costs for the next few results. This suggests that a more selective display should look at the routes up to about $90 million:

In general:

• Routes converging to pass through a narrow corridor indicate their importance in containing costs.

• Routes fanning out indicate that cost is not an important driver in the alignment in plan and therefore provides more flexibility to satisfy other criteria with minimal impacts to costs.

Next topic: Mass Haul Diagram