staple

A staple is a subsidiary shaft sunk between two or more working levels in a mine, serving as a connection for personnel, materials, and ventilation air. Unlike the main shaft, which may be several hundred metres deep and handle the bulk of hoisting operations, a staple is typically narrower, shorter, and engineered to link specific sections of the mine horizontally separated by depth. It allows miners to move between levels without returning to surface, reducing transit time and improving operational efficiency.

Staples are essential in hard rock mining, particularly in deep metalliferous operations where multiple productive seams or ore bodies exist at different elevations. A single mine may have several staples distributed across the property, each serving a particular section or district. The shaft is usually fitted with a fixed ladder or cage, or both, and includes provisions for compressed air lines and sometimes water pipes. Ventilation through staples is critical: they often form part of the return air circuit, carrying spent air from working areas back toward surface.

Construction and dimensions

Staples are typically 1.5 to 3 metres in diameter, depending on ore body geometry and extraction method. They may be lined with timber sets or steel, and in older mines, often remain unlined in solid rock where geotechnical conditions permit. The vertical distance between levels they connect ranges from 30 to 100 metres, though longer examples exist in deep mines. Collar collars are reinforced; the shaft is sunk using conventional drilling, blasting, and mucking, and is then fitted with safety infrastructure before use.

The term itself derives from the mining practice of using staples or large iron hoops to hold timber framing together; the staple shaft became the obvious name for a smaller connecting shaft. In South African and Australian mining terminology, staples are sometimes called winzes if they are driven upward from a lower level toward a higher one, though usage of these terms overlaps and regional conventions vary. A staple driven downward from surface into a developing area may be called an internal shaft to distinguish it from a perimeter main shaft.

Maintenance and collapse are persistent concerns. Water ingress, rock fall, and timber decay compromise safety and airflow control. Modern staples in active mines are inspected regularly and may be fitted with scaling bars, netting, or bolting to manage geotechnical hazards. Abandoned staples that are not properly sealed pose ventilation and ground control risks to adjacent workings.