Open-pit mining methods

Benching mining is a technique whereby an open-pit mine is subdivided into multiple level benches, each possessing a specific height and width, with stripping and mining operations conducted sequentially.

This method is suitable for open-pit mines with favourable ore body conditions and relatively hard rock. Its technical characteristics include relatively gentle working slope angles, typically ranging from 8° to 15°, while bench height depends on factors such as ore body structure, rock properties, and mining intensity. For rock requiring blasting, bench height is usually set at 1 to 1.25 times the maximum digging height of excavators. The bench mining method offers advantages including large-scale stripping and extraction capabilities, high mining efficiency, and strong equipment adaptability, being suitable for various types of mining machinery such as single-bucket excavators and rotary drill rigs. However, it also presents certain drawbacks, such as substantial initial investment and extensive infrastructure requirements, leading to higher upfront costs. Additionally, it features a high stripping ratio, resulting in significant rock removal during the early stages of mining.

Steep-Bench Mining effectively delays the stripping peak and increases reserve ore volume by steepening the working bench angle, thereby enhancing mine production capacity. Its technical characteristics include a steeper working bench angle, typically greater than that of gentle-bench mining, which reduces initial stripping volume. This method is suitable for open-pit mines with complex ore body conditions and high stripping ratios. Its advantages lie in effectively lowering the stripping ratio during the initial mining phase, increasing the volume of reserve ore, and enhancing both mine production capacity and resource utilisation efficiency. However, this mining approach demands high technical standards, requiring precise mining design and rigorous production management to ensure slope stability.