http://www.dailykos.com/storyonly/2006/1/2/84040/12187
First, resources are fundamentally different from manufacturing, in that manufacturing is wide spread, but resiliant. Resources are concentrated, but brittle. This makes a difference both during escalating tensions, and for the possibility of all out war. The resiliant nature of manufacturing means that pin prick military actions are generally worthless. Bomb one plant, and the equipment will be moved to another. Extraction is the reverse - it is rife with fragile infrastructure that is very worth destroying - oil refineries, petrol storage facilities, oil and gas pipelines and nuclear reactors for enriching Uranium - are all fragile and expensive, and generate economic benefit far out of proportion to their size.