Resources refer to mineral deposits that are potentially recoverable and may be of economic interest. Reserves are a category of resources that have been proven to be practical to extract for a profit.
Another way of thinking about the difference between resources and reserves is the amount of planning that goes into developing the data. A resource can be determined by analyzing geological data to determine the extents of the deposit. Reserves may lie within that resource. To determine the extent of the reserves, a full feasibility study must be performed
Figure: Resources vs. reserves