Abstract: On July 13, 2010, an employee was working for a drilling company as a helper. The employer was a subcontractor drilling pier holes to install lagging at the backyard of a residential house. The employer operated a Takeuchi Model TB53FR, a mini diesel drill rig to drill a hole with an auger attachment. The hole was 30-in. in diameter and approximately 10-ft deep. They were working together to remove the auger attachment so that they could insert a Sonotube that was 24-in. in diameter by 6-ft long. The employer had placed some plywood over the hole for both of them to stand on. The employer was on one side of the auger shaft to knock out some pins to disconnect the auger from the drill rig. At approximately 1:00 p.m., a nearby column, approximately 5 feet away, kicked-out as well as a section of the backyard slab had broken-off. Both pieces fell into the hole first, as it pushed apart the plywood nearly striking the employee and slightly glanced the employer. When the plywood was displaced, the employee also fell into the hole followed by his employer. The employer and the employee were both buried. The employee was buried up to his mouth. His employer, who was above the employee, was buried up to his waist. The employer quickly dug himself out and was also trying to dig sand away from the employee's mouth and nose. A coworker of the general contractor was passing by when he noticed there was a problem and called the emergency services. The city fire department, paramedics, police department, building inspectors, and the media were at the scene. The employee was given IV, oxygen and water to drink while he was buried approximately 4 hours. After the employee was rescued, he was taken by ambulance to SF General Hospital. The employee was treated for minor bruises and was released later that evening.