Study on developing a technological process for recovering protective coal pillars in depleted underground mining areas

In underground coal mining operations in Quang Ninh, leaving the coal pillars as protection for the roadways and underground works has caused great losses. Re-mining of these leftover coal reserves will not only maximize the recovery rate but also prolong the life span of mines through improving the overall socio-economic efficiency of mining enterprises. The purpose of this research is to provide a practical combination of technological and engineering solutions that will ensure high productivity for residual coal pillar re-mining from exhausted underground mining areas. The end purpose here is to determine an optimized technical parameter set guided by safe, feasible mining processes that can serve as a base for further large-scale applications, plus improved efficiency in recovering more coal. A geological survey was carried out at Nam Mau mine, based on which a technological solution was proposed, including the following steps: geological investigation; design of access roadways; mining using shortwall or surrounding roadway systems; strata control; and effective ventilation. Also, a secure and handy extraction method fine-tuned by real-world tests was set up. The fresh tech route got rated as very doable, bringing big money gains with a 10–15% boost in coal get back rate plus an 8–12% drop in road making costs against old ways. This method can see broad use in under-the-surface pits in Quang Ninh, along with other pits having similar geo-tech setups.

Hoang Hung Thang, Golik V. I. Study on developing a technological process for recovering protective coal pillars in depleted underground mining areas. MIAB. Mining Inf. Anal. Bull. 2026;(7):49-67. DOI: 10.25018/0236_1493_2026_7_0_49.

Dr. Hoang Hung Thang, Rector of Quang Ninh University of Industry, Quang Ninh province, Vietnam, e-mail: hoanghungthang@qui.edu.vn, Scopus ID 57225075880, ORCID ID: 0009-0003-4031-977X,
V.I. Golik, Dr. Sci. (Eng.), Professor, Professor, Moscow Polytechnic University, 107023, Moscow, Russia, e-mail: v.i.golik@mail.ru, ORCID ID: 0000-0002-1181-8452.

Hoang Hung Thang, e-mail: hoanghungthang@qui.edu.vn.

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