The Collaborative International Dictionary of English v.0.48:

Mintage \Mint"age\, n.
   1. The coin, or other production, made in a mint.
      [1913 Webster]

            Stamped in clay, a heavenly mintage.  --Sterling.
      [1913 Webster]

   2. The duty paid to the mint for coining. At one time people
      could bring precious metals, as gold or silver, to a mint
      and receive in return coins of the same value, minus the
      commision charged by the mint, which was the mintage.
      [1913 Webster +PJC]

   3. The act or process of minting[1]; as, a coin of recent
      mintage.
      [PJC]

   4. The quantity of coins of a specific type made by the mint;
      as, coins of low mintage tend to be more valuable as
      collectors' items.
      [PJC]

WordNet (r) 3.0 (2006):

mintage
    n 1: coins collectively [syn: coinage, mintage, specie,
         metal money]
    2: fee paid to a mint by the government for minting a coin
    3: act or process of minting coins

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "mintage":
   and pence, artifact, authorship, beginning, brainchild, cash,
   child, circulating medium, coinage, coined liberty, coining,
   cold cash, composition, conception, concoction, contrivance,
   contriving, counterfeiting, creation, creative effort, creature,
   crowning achievement, currency, devising, distillation, dollars,
   effect, emergency money, end product, essence, extract,
   fabrication, filthy lucre, forgery, fractional currency, fruit,
   generation, gold, handiwork, hard cash, hard currency, hatching,
   improvisation, invention, issue, legal tender, lucre, making do,
   mammon, managed currency, manufacture, masterpiece, masterwork,
   medium of exchange, money, necessity money, new mintage, offspring,
   opera, opus, opuscule, origination, outcome, outgrowth, pelf,
   postage currency, postal currency, pounds, product, production,
   result, scrip, shillings, silver, soft currency, specie, stamping,
   sterling, striking, the almighty dollar, the wherewith,
   the wherewithal, work