A method for drying of geological material having a substantial moisture content, the method comprising: providing a flow of heated fluid through a passage having a longitudinal axis (X) from an upstream end toward an end downstream thereof; wherein the downstream end of the passage is arranged in fluid communication with a collection means so that dried material can be collected thereby for subsequent processing; wherein the flow of heated fluid is provided by a heat source arranged so that heated fluid can be introduced into the passage in a tangential manner and a fluid distribution assembly , the fluid distribution assembly comprising a means for establishing a region of low pressure downstream of the heat source so as to, at least in part, cause the flow of the heated fluid and/or carriage of dried material towards the collection means ; exposing a portion of the sample of geological material to the flow of heated fluid; and controlling a thermal state of the flow of heated fluid so as to cause a reduction of the moisture content of the portion of the sample of material while the temperature of the portion is maintained below a predetermined temperature level in order to preserve one or more chemical and/or physical properties of the portion; characterized in that the fluid distribution assembly comprises a fluid mixing assembly configured for causing, at least in part, rotational, non-linear, or unsteady flow of the fluid as it progresses downstream; wherein the fluid mixing assembly is arranged so as to be movable in a direction aligned with the longitudinal axis (X) of the passage for, at least in part, modifying and/or controlling the flow of heated fluid; wherein the fluid mixing assembly comprises a rotating member having one or more fluid engaging members extending therefrom, the or each fluid engaging member configured for engaging with the heated fluid. providing a flow of heated fluid through a passage having a longitudinal axis (X) from an upstream end toward an end downstream thereof; wherein the downstream end of the passage is arranged in fluid communication with a collection means so that dried material can be collected thereby for subsequent processing; wherein the flow of heated fluid is provided by a heat source arranged so that heated fluid can be introduced into the passage in a tangential manner and a fluid distribution assembly , the fluid distribution assembly comprising a means for establishing a region of low pressure downstream of the heat source so as to, at least in part, cause the flow of the heated fluid and/or carriage of dried material towards the collection means ; exposing a portion of the sample of geological material to the flow of heated fluid; and controlling a thermal state of the flow of heated fluid so as to cause a reduction of the moisture content of the portion of the sample of material while the temperature of the portion is maintained below a predetermined temperature level in order to preserve one or more chemical and/or physical properties of the portion; characterized in that the fluid distribution assembly comprises a fluid mixing assembly configured for causing, at least in part, rotational, non-linear, or unsteady flow of the fluid as it progresses downstream; wherein the fluid mixing assembly is arranged so as to be movable in a direction aligned with the longitudinal axis (X) of the passage for, at least in part, modifying and/or controlling the flow of heated fluid; wherein the fluid mixing assembly comprises a rotating member having one or more fluid engaging members extending therefrom, the or each fluid engaging member configured for engaging with the heated fluid. <EOS>