No beds of wagons, cars or carts, except those from which coal is sold and delivered, shall require the sealer's mark, nor shall the standard of weight be applied where the coal stands in the bed up to the sealer's mark at which it is proposed to sell. Provided, That the miner or miners using the car or cars to convey the coal from the pit to the platform, can at any time they suspect the measurement allowed to any car or cars, compel the employer or employers to have the same measured and branded by the sealer of weights and measures, under the penalty heretofore enacted for refusal to have the sealer's mark or brand placed on the cars, carts and wagons.