4. The meeting of grassroots-level assessment, acceptance of the study

On December 01, 2016, Technology & science enterprise – VIMCC Company held the meeting of grassroots-level assessment, acceptance of the study “Research for completing the road supporting and driving technology by bolting + steel mesh + spraying concrete for supporting the weak rock roadways”.

    In order to meet the increasingenergydemand, the coal mining output requires higher volume corresponding to the larger mining depthand driven road meter-volume. On the other hand, according to statistics in recent years, the volume of roadways has reached approximately 300 km/year and this figure will increase by about 5 ÷ 7% per year. The roadways are mainly supported by the steel bolting-traditional supporting structure. Therefore, Vinacomin had the positive policies and mechanismsin order to promote to replace with the bolting + spraying concrete-new supporting structure. However, the annual gained bolting-supported road meter-volume is limited because the supporting structure is applied to the stable and strong rock cases.

       The road supporting by bolting structure in weak rock has not been studied in detail. Currently, the bolting supporting technique in several countries with advanced mine construction technique such as Japan, China has been gained a new advance which the normal steel bolting is used combining with rope bolting to increase the force-bearing capacity of the supporting structure. The combination between rope bolting and normal steel bolting created an optimal supporting structure complex for roadways with high pressure driven in weak rock. Although the combination between steel bolting and prestressed rope bolting is used widely around the world but in Vietnam it is tested in Ha Lam coal mine by the co-ordination between VIMCC and Ha Lam Coal Company, the initial result is positive and satisfactory.

       The main contents of the study:

1-The actual state of road supporting and driving by bolting at Vinacomin’s units;

2-General overview of the resin-using rope bolting;

3-General overviewon the Sika Rokkon adhesive material (using for steel bolting);

4-Selecting and completing the technology of using the steel bolting – rope bolting structural complex for supporting the weak rock roadways;

5-The result of weak rock road supporting by bolting in Ha Lam coal mine;

At the meeting, the members of the Council contributed many opinions to completing  the summary report of the study before the study is submitted to the Vinacomin-level technological and scientific Council for approval./.

By: Minh Nguyen-Thu Thuy