As an occupier, you do not need to get approval to set up the work process but you must to comply with the requirements under the WSH (General Provisions) Regulations.
Section 26 of the WSH (General Provisions) Regulations states that for process which gives rise to dust, gas, vapour or substance that may escape into any place of work.
The dust, gas, vapour or substance that may escape is liable to explode on ignition (in this case combustible dust), measures need to be in place to prevent such explosion.