The Brikama-born player opened the scoring for The Miners in the 37th minute of the first half, before also wrapping the score-line with second goal in the 70th minute of the second half.
Julius Szoke and Valon Ahmedi scored the other two goals for the Shakhtyor in the 41 and 54th minute of the game.
The former Real De Banjul and Ndiambour player has now scored three league goals (against Minsk and Isloch) for Shakhtyor after three games.
Dembo signed for the Belarusian side after leaving the Macedonian side Shkupi last summer
The win moved Dembo Darboe and his Shakhtyor side to top of the Belarusian Premier League with 9 points while Isloch sits fifth position with 6 points after three matches.