Drowning is the number one cause of death in abandoned mines. Most people involved in this type of accident went to a quarry for swimming. Quarries are extremely dangerous places to swim. Steep drop-offs, deep water, sharp rocks, flooded equipment, submerged wire, and industrial waste make swimming risky.

Another risk factor is the very cold water. Many quarry operations excavate to depths below the water table and use pumps to keep the mine dry while it is in operation. When mining stops, the pumps are turned off and the quarry floods by the inflow of cold groundwater. This groundwater inflow can keep the quarry water very cold even in late summer.

Jumping or falling into cold water can be fatal – even for a young healthy person. Here is a quote from the National Institute of Health on how a body responds to sudden immersion in cold water…

A fall in skin temperature elicits a powerful cardiorespiratory response, termed “cold shock,” comprising an initial gasp, hypertension, and hyperventilation despite a profound hypocapnia. […] The respiratory responses to skin cooling override both conscious and other autonomic respiratory controls and may act as a precursor to drowning.