WordNet (r) 3.0 (2006):

spadework
    n 1: dull or routine preliminary work preparing for an
         undertaking

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "spadework":
   arrangement, basic training, briefing, clearing the decks,
   dirty work, donkeywork, drudgery, employment, equipment, fag,
   familiarization, fatigue, fixing, foundation, grind, groundwork,
   handiwork, handwork, industry, labor, lick, lick of work,
   makeready, making ready, manual labor, manufacture, mobilization,
   moil, planning, prearrangement, preliminaries, preliminary,
   preliminary act, preliminary step, prep, preparation,
   preparatory study, preparing, prepping, prerequisite, pretreatment,
   processing, propaedeutic, provision, rat race, readying, scut work,
   slavery, stroke, stroke of work, sweat, task, tiresome work, toil,
   training, travail, treadmill, treatment, trial, tryout, warm-up,
   work