Sentence:  The product described in the earlier contract is: / 'All the zinc sulphide crude ore, zinc sulphide concentrates and zinc sulphide <WSD>middlings</WSD>, shipped from Midvale, Utah, Kennett, Cal., or any other point by or under the control of the seller during the period of this agreement.' 
Meaning of the word marked with <WSD> tags:  Partially refined ore or petroleum.