Employees were setting braces on a vertical wall. They had it rigged up using a jib pole attachment on a front-end loader. They secured a brace and an employee went up a ladder to disconnect the rigging from the hook. The injured employee was holding the ladder. The jib pole attachment (estimated to weigh 2,000 pounds) detached from the loader, struck the injured employee, and pinned him against the ladder. The employee was hospitalized with multiple injuries including a punctured lung, fractures to his collarbone, arm, and femur, and injuries to his hip and leg.