Precast Concrete Industry – Application Series: 1 of 5 Gravel Pits: Conveyor Systems

Precast Concrete Industry – Application Series: 1 of 5

Gravel Pits: Conveyor Systems – Trapped Key Interlock Safety Solutions

40 workplace fatalities and 9,000 injuries a year are the result of conveyor accidents as reported by the U.S. Department of Labor

The extraction or storing of aggregate within a gravel pit serves a variety of purposes across many industries including the concrete & cement industries.

Conveyor systems are an important method in the process of transporting materials across the mine surface, into hoppers, over grating for sorting, and into trucks for distribution to plants and manufacturing facilities.

Conveyor system injuries account for 25% of all workers’ compensation claims

The continuous movement of belts, chains, and diverters place personnel working and operating the system at risk. Regular maintenance on these systems is required to ensure efficiencies. Safety processes must be followed to mitigate human error and save lives. The isolation of power prior to entry into the area is the first step in mitigating risk.

Trapped key interlocking systems are recognized by ANSI/ASSE Z244.1 as an Alternative LOTO measure

Trapped key interlock safety solutions ensure a pre-determined sequence of operations each & every time.  While LOTO provides a visual warning and identifies hazards, a TKI solution physically prevents a specific set of actions from being performed until previous action(s) have been fully completed!

Common trapped key interlock solution interlocking conveyor system with multiple access points and access doors:

Step 1: Power Isolation KIRK Type F isolation interlock installed on main breaker for conveyor

Step 2: Multiple Entry Points KIRK Type T transfer interlock for access to multiple hopper access doors

Step 3: Safe Access KIRK Type D access lock installed on hopper doors

Step 4: Controlled Power KIRK Type PPS electromechanical interlock installed on control switch for hopper doors

Download the pdf version of this first part of our Precast Concrete Application Series focusing on how trapped key interlocking solutions can mitigate human error and save lives when operating conveyor systems within gravel pits.