A method and apparatus for adding an additive material, such as a fluid (gas or liquid) to a granular base material which is to be compacted, providing for maximum saturation of the granular base material with the fluid by injecting the fluid into the granular base material in metered proportions prior to or during the compacting operation. The method may be advantageously carried out in an apparatus such as a compacting press having a die provided with at least one die cavity into which a lower compacting member extends for movement upwardly through the die cavity. The die cavity is filled with a granular base material from a filling head positioned above the die cavity. The filling head is part of a positioner assembly pivotally supported over the die cavity and which comprises, in addition to the filling head, an anvil or upper compacting member adapted to be placed over the filled die cavity for compression of the granular material between the anvil or upper compacting member and the lower compacting member. The fluid, under controlled pressure and in a predetermined amount, is injected into the granular base material immediately prior to or during advancement of the lower compacting member within the die cavity for compression of the granular material into a fluid-saturated compacted article, and thereafter the fluid-saturated compacted article is ejected from the die cavity for disposal into a suitable receptacle.