WordNet (r) 3.0 (2006):

dig up
    v 1: find by digging in the ground; "I dug up an old box in the
         garden" [syn: excavate, dig up, turn up]
    2: remove, harvest, or recover by digging; "dig salt"; "dig
       coal" [syn: dig, dig up, dig out]

Moby Thesaurus II by Grady Ward, 1.0:

127 Moby Thesaurus words for "dig up":
   accumulate, agglomerate, aggregate, aggroup, amass, assemble,
   avulse, batch, be curious, bring to light, bring together, bulk,
   bunch, bunch together, bunch up, burn with curiosity, clump,
   cluster, collect, colligate, collocate, combine, compare, compile,
   conglomerate, corral, cull, cumulate, cut out, deracinate,
   dig around for, dig out, disclose, disentangle, disinter, draw,
   draw out, draw together, dredge, dredge up, drive together,
   eradicate, evolve, evulse, excavate, excise, exhume, expose,
   exsect, extract, extricate, ferret out, fish up, gape, gather,
   gather in, gather together, gawk, get in, get out, get together,
   glean, gouge out, group, grub, grub up, inquire, interrogate, join,
   juxtapose, lump together, make up, mass, match, mine, mobilize,
   muster, nose around for, nose out, pair, partner, peer, pick,
   pick out, pick up, pluck, pluck out, pluck up, pull, pull out,
   pull up, put together, quarry, query, question, quiz, raise,
   rake out, rake up, rally, remove, reveal, rip out, root out,
   root up, round up, rubber, rubberneck, scare up, scrape together,
   scrape up, seek, stare, take out, take up, tear out, turn up,
   uncover, unearth, unravel, uproot, want to know, weed out, whip in,
   withdraw, worm out, wrest out