57(1)The Commission may establish such sub-classifications, differentials and proportions in the rates as between the different kinds of employment in the same class as may be deemed just; and where any particular industry is shown to be so circumstanced or conducted that the hazard is greater than the average of the class or sub-class to which such industry is assigned, the Commission may impose upon such industry a special rate, differential or assessment, to correspond with the excessive hazard of such industry.