Comparative Analysis and Optimization of Deep Mining Technologies for Gold Ore Bodies

Deep mining of gold ore bodies has become a focal point in the mining industry due to its unique geological conditions and technical requirements. Deep ore body mining involves significant depths and complex geological structures, presenting multiple risks such as dynamic hazards, ground pressure control, and ecological damage. Potential accidents like rock bursts and subsidence in abandoned areas, along with environmental issues like waste residue and wastewater discharge, and surface subsidence, impose stringent demands on the safety and rationality of mining techniques. To achieve a win-win outcome between mining efficiency and safety assurance, it is necessary to select the optimal mining technology through comparative analysis of multiple schemes.

This study examines three mainstream approaches: upward-level point-pillar non-cemented filling, upward-level layered and drift cemented combined filling mining, and pre-controlled roof segmental post-mining filling. A comprehensive comparison is conducted across structural parameters, development and caving methods, mining processes, and technical-economic indicators. The upward-level point-pillar non-cemented backfill method (Scheme 1) employs a vertical ore body distribution within the mining room. The panel area is divided into four blocks, each 15m wide, supported by 4m×4m point pillars. The single-stage height is 60m, utilizing tailings backfill with a reserved 2m–3.5m void height. This scheme achieves a daily production capacity of 302 tons but suffers from a 31% dilution rate, 19% loss rate, and a poor cut-to-ore ratio of 15.4m/kt, resulting in suboptimal overall efficiency.

The upward-level layered mining combined with drift grouting backfill method (Scheme 2) optimizes block division. Each panel is divided into 7 blocks, each 9m wide, employing an alternate mining pattern. Mining proceeds upward in horizontal layers with backfill, requiring phased curing and strength testing post-backfill. This approach improved metrics with a daily output of 404 tons, reducing dilution and loss rates to 8% each. However, it featured a high cut-to-fill ratio of 24.9m/kt, higher engineering costs, and increased management complexity due to numerous blocks.

The pre-controlled roof sectional delayed backfilling method (Scheme Three), as an optimized upgrade, demonstrates outstanding comprehensive performance. Its chamber design and sectional layering parameters are scientifically sound. Medium-deep hole mining technology significantly reduces engineering volume. The extraction process occurs in two stages—chamber and pillar—with efficient coordination between blasting and backfilling operations. Technical and economic indicators show this method operates 10 mining blocks simultaneously, achieving a daily production capacity of 588 tons with a cut-to-ore ratio of only 12.5m/kt. Equipment operational efficiency remains stable across all categories. Industrial trials further validate its advantages: mining costs are ¥275/ton, backfilling costs are ¥23/ton, and beneficiation costs are ¥155/ton, maximizing economic benefits while ensuring safety.

Comparative analysis reveals that the pre-controlled roof sectional delayed backfilling method outperforms the previous two approaches in production capacity, resource recovery rate, and cost control. It also effectively addresses safety risks in deep mining, providing reliable technical support for deep gold mining operations and serving as a valuable reference for similar projects.