Requirements for selection and arrangement of exploration works in Vietnam

Requirements for selection and arrangement of exploration works in Vietnam - Illustrative image

Article 13 of Circular 74/2015/TT-BTNMT stipulates the requirements for selection and arrangement of exploration works as follows:

1. Selection of exploration works

- In exploring apatite, various excavation works (trenches, pits, shafts) and drilling can be selected. The selected exploration works must be suitable for the following conditions: dip angle, distribution depth, geological structure, morphology, thickness of each ore body, and the characteristics of the overburden;

- b) At the exploration works, detailed samples must be taken to determine the quality, distribution rules of ore types, weathering depth, structural characteristics of the walls, and pillars of the ore body;

- c) For mines with very complex geological structures, to clarify the dip angle conditions, shape, internal structure of the ore body, exploration works such as shafts and pits should be used, limiting the use of drilling works

;- Core drilling must recover the highest possible amount of intact core. The sampling ratio of core drilling must not be less than 70% through rock sections and 85% when drilling through ore. It is encouraged to use combined geophysical borehole methods;

- Vertical boreholes over 100 meters deep and inclined boreholes must have their orientation and deviation measured every 10 to 20 meters;

- For steep or vertical dipping ore bodies, inclined or horizontal drilling methods should be applied;

- Exploration works must cut through the entire thickness of the ore body.

2. Arrangement of works and selection of exploration network density

- The arrangement of exploration works must ensure a comprehensive assessment of geological structural characteristics, morphology, dimensions, dip angle conditions, and the stability of the ore body's thickness;

- The orientation network for exploration works is prescribed in Appendix 2 attached to this Circular;

- Exploration works, mining works, natural and artificial outcrops within the exploration area must be described, geologically mapped, and the original data must be promptly, fully, and accurately established following current regulations on original data collection in mineral exploration and must be plotted on the actual data map.

Detailed content is in Circular 74/2015/TT-BTNMT, which takes effect on February 15, 2016.

Le Vy

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