225 ILCS 705/32.03

The miners at work in any coal mine may employ a check weighman at their option and at their own expense, whose duty it shall be to balance the scales and see that the coal is properly weighed, and that a correct account of the same is kept, and for this purpose he shall have access at all times to the beam box of the scales, and be afforded every facility for verifying the weights while the weighing is being done. The check weighman so employed by the miners shall be a citizen of the United States or lawfully admitted for permanent residence and, before entering upon his duties, shall make and subscribe to an oath, before some person duly authorized to administer oaths, that he will faithfully discharge his duties as check weighman, and such oath shall be kept conspicuously posted at the place of weighing.