This situation occurs during dosage of the basic components of a recipe, i.e. the ingredients that account for 80<90% of the whole formulation. Since these are large amounts of powdery ingredients, they are often provided via silos pneumatically loaded from tank trucks. 
This is often the first dosing process, to which small amounts of minor ingredients are added in special microdosing stations. 
Silos are always equipped with a bin activator or other equipment which enables the product to flow. 
The dosing process is always performed employing progressive cavity dosing screws.
Since high dosing accuracy is rarely required, there is no need to employ double spiral dosing screws. 
Example:
It is possible to dose 500 Kg of wheat flour using a Ø 200 mm screw in about 180 seconds, with an accuracy of +/- 0,7% = +/- 3,5 Kg.