Beginning in the early part of the 20th century, each CF&I employee was assigned a number which was used for both payroll purposes and employee identification. These numbers were stamped on what were known as brass checks, or small squares of brass the employee carried with them at all times, often attaching it to his or her keyring or a key fob and hooked to a belt loop.
For CF&I miners, the brass checks served two purposes. Not only were they used for identification purposes when payday rolled around, but when entering the mine, each man’s check was taken off a board and then replaced on the board when he exited the mine. This let supervisors and other employees know which miners and how many were in the mine at any given time. This was particularly important when an accident such as cave-in or a scheduled blast of dynamite occurred. Miners also hung their check on the coal cars they filled to receive credit for that day’s work.
By the time CF&I started using computers in the late 1960s to track time and manage the payroll department, brass checks were replaced with computerized versions with the employees’ name, number and a small head shot photograph of the employee.