Strip mining is a term used for harvesting the resources in a field to low levels. Since the amount of a resource produced by a field depends on the amount already in it (except for Exotic Matter), this is universally regarded as wasteful and damaging to the economy and environment. It is especially loathed when done on fuel tiles, as this requires everyone to pay for expensive Fuel Collector or Black Market fuel, and increases the danger inherent in running out of fuel.
Note that what is considered strip mining heavily depends on context. For example, a fuel tile with 100 fuel in a crowded faction homeworld sector would be considered abundant; a fuel tile with 100 fuel in an alliance-owned nook would be considered chronically stripmined.