(ZA9610679-A)      Nickel is recovered from a Ni-containing lateritic ore (I) or a Ni-containing sulphidic ore or concentrate (II) by bioleaching a slurry, heap or vat of the ore, to effect dissolution of the Ni and form a pregnant solution (III) and a residue, separating (III) from the residue, contacting (III) with an ion exchange resin (IV) containing bis-picolylamine specific to absorption of Ni, to form a Ni-loaded resin (V), extracting Ni from (V) with a mineral acid solution (IV), and recovering Ni from (VI). When the ore is (I), the microorganism (A) used in the leaching is a fungi (or bacteria) that systemically produces a carboxylic acid conductive for chelating Ni, pH is maintained at 1-3, and a nutrient for (A) is present. When the ore is (II) or a concentrate thereof, the microorganism (B) is a biooxidising bacterium selective for leaching (II), pH is maintained at 1-3 and a nutrient for (B) is present; (B) is at least one of Thiobacillus thiooxidans or ferrooxidans, Leptospirit um species, Sulphobacilus, thermosulphidoxidans or similar species, or Sulpholobus BC or sulphataricus.    USE -   Low grade and relatively high grade ores are treated economically and efficiency, without going through an intermediate nickel sulphide stage.    (WO9826100-A1)      Nickel is recovered from a Ni-containing lateritic ore (I) or a Ni-containing sulphidic ore or concentrate (II) by bioleaching a slurry, heap or vat of the ore, to effect dissolution of the Ni and form a pregnant solution (III) and a residue, separating (III) from the residue, contacting (III) with an ion exchange resin (IV) containing bis-picolylamine specific to absorption of Ni, to form a Ni-loaded resin (V), extracting Ni from (V) with a mineral acid solution (IV), and recovering Ni from (VI). When the ore is (I), the microorganism (A) used in the leaching is a fungi (or bacteria) that systemically produces a carboxylic acid conductive for chelating Ni, pH is maintained at 1-3, and a nutrient for (A) is present. When the ore is (II) or a concentrate thereof, the microorganism (B) is a biooxidising bacterium selective for leaching (II), pH is maintained at 1-3 and a nutrient for (B) is present; (B) is at least one of Thiobacillus thiooxidans or ferrooxidans, Leptospirit um species, Sulphobacilus, thermosulphidoxidans or similar species, or Sulpholobus BC or sulphataricus.    USE -   Low grade and relatively high grade ores are treated economically and efficiency, without going through an intermediate nickel sulphide stage.    (EP948655-A1)      Nickel is recovered from a Ni-containing lateritic ore (I) or a Ni-containing sulphidic ore or concentrate (II) by bioleaching a slurry, heap or vat of the ore, to effect dissolution of the Ni and form a pregnant solution (III) and a residue, separating (III) from the residue, contacting (III) with an ion exchange resin (IV) containing bis-picolylamine specific to absorption of Ni, to form a Ni-loaded resin (V), extracting Ni from (V) with a mineral acid solution (IV), and recovering Ni from (VI). When the ore is (I), the microorganism (A) used in the leaching is a fungi (or bacteria) that systemically produces a carboxylic acid conductive for chelating Ni, pH is maintained at 1-3, and a nutrient for (A) is present. When the ore is (II) or a concentrate thereof, the microorganism (B) is a biooxidising bacterium selective for leaching (II), pH is maintained at 1-3 and a nutrient for (B) is present; (B) is at least one of Thiobacillus thiooxidans or ferrooxidans, Leptospirit um species, Sulphobacilus, thermosulphidoxidans or similar species, or Sulpholobus BC or sulphataricus.    USE -   Low grade and relatively high grade ores are treated economically and efficiency, without going through an intermediate nickel sulphide stage.