Classification of Groups of Mines for Exploring Primary Gold Mineral Resources

In accordance with Article 9 of Circular 03/2015/BTNMT, the division of exploration mine groups is prescribed as follows based on the following grounds:

Division of primary gold mineral exploration mine groups (Illustrative image)

- Based on the shape, size, and position of primary gold ore bodies, the stability of thickness, variation of gold content, and complexity of geological structure of the mine;

- Based on quantitative indices evaluating the variation of thickness, content of ore bodies, and geological conditions for mining in order to divide exploration mine groups;

- Based on specific arguments and evaluations of the main primary gold ore bodies, which account for no less than 70% of the mine's reserves. The exploration mine groups are projected in the Mineral Exploration Scheme and determined in the Mineral Exploration Result Report.

Division of exploration mine groups into groups:

- Simple mine group (I);- Relatively complex mine group (II);- Complex mine group (III);- Very complex mine group (IV).

Conditions for grouping exploration mines

- Simple Mine Group (I):

Including mines or parts of mines with simple geological structures with vein-shaped ore bodies, large lenses that lie horizontally or gently slope, ore bodies with simple shapes; stable ore body thickness, thickness variation coefficient according to work not greater than 40%; the main useful components evenly distributed, the content variation coefficient according to individual samples not greater than 40%, and ore-bearing coefficient from 0.8-1.0;

- Relatively Complex Mine Group (II):

Including mines or parts of mines from large to medium, relatively complex geological structures with vein-shaped ore bodies, large veins, lenses; relatively stable to unstable ore body thickness, thickness variation coefficient according to work from above 40% to 100%; the main useful components distribution in ore bodies from relatively even to uneven, the content variation coefficient according to individual samples from above 40% to 100%, and ore-bearing coefficient from 0.7 to 0.8;

- Complex Mine Group (III):

Including mines or parts of mines from small to medium with complex geological structures with ore bodies in shapes like layers, veins, lens veins, clusters, columns, pipes; complex shapes of ore bodies, unstable ore body thickness, thickness variation coefficient according to work from above 100% to 150%; the main useful components unevenly distributed, the content variation coefficient according to individual samples from above 100% to 150%; ore-bearing coefficient from 0.6 to 0.7;

- Very Complex Mine Group (IV):

Including mines or parts of mines with very small to small geological structures very complex, with ore bodies of small to very small sizes, vein shapes, network veins, lens veins, columns, clusters...; very complex shapes of ore bodies, particularly unstable ore body thickness, thickness variation coefficient according to work above 150%; the main useful components' content variation particularly uneven, the content variation coefficient according to individual samples above 150%; ore-bearing coefficient below 0.6.

For more details, refer to Circular 03/2015/BTNMT, effective from April 1, 2015.

Thu Ba

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