SHANGHAI, Apr 28 (SMM) - On April 28, premiums of Jinchuan nickel were 3,500-4,000 yuan/mt. The average premium stood at 3,750 yuan/mt, down 350 yuan/mt from the previous trading day. NORNICKEL nickel was quoted at premiums of 2,000-2,500 yuan/mt, with an average premium of 2,250 yuan/mt, down 400 yuan/mt from a day ago. Spot suppliers were active in shipping at the month-end, and the supply of imported pure nickel grew, dragging down spot premiums. Nickel briquette prices were 190,300-191,700 yuan/mt, an increase of 4,500 yuan/mt from the previous trading day. The nickel briquette transactions were slack as it was still traded at premiums over nickel sulphate.