 Dorchester Minerals NASDAQ:DMLP was downgraded by TheStreet from a b rating to a c rating in a report released on Tuesday, TheStreetRatingsTable reports. Separately, BidaskClub lowered Dorchester Minerals from a sell rating to a strong sell rating in a report on Tuesday, February 11th. NASDAQ:DMLP traded down 0.04 during midday trading on Tuesday, reaching 14.55. ... 