Circular No. 05/2020/TT-BTNMT stipulates technical aspects of exploration and assessment of block stone reserves for tiling and decorative purposes.

CIRCULAR

TECHNICAL REGULATIONS ON EXPLORATION AND ASSESSMENT OF BLOCK STONE RESERVES USED FOR TILING AND SCULPTURE
Pursuant to the proposal of the General Department of Geology and Mineral Resources of Vietnam, the Department of Science and Technology, and the Legal Affairs Department;

Pursuant to the Minerals Law No. 60/2010/QH12 dated November 17, 2010;

Pursuant to Decree No. 158/2016/NĐ-CP dated November 29, 2016 of the Government detailing the implementation of certain articles of the Law on Minerals;

On the basis of Decision No. 36/2017/NĐ-CP dated April 4, 2017, of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Natural Resources and Environment;

The Minister of Natural Resources and Environment promulgates this Circular on technical regulations for exploration and assessment of block stone reserves used for tiling and sculpture;

This Circular stipulates technical regulations for exploration and assessment of block stone reserves used for tiling and sculpture.

Article 1. Scope of Regulation

This Circular applies to state management agencies for minerals, organizations, and individuals related to activities of exploration and assessment of block stone reserves used for tiling and sculpture.

Article 2. Applicability

Block stone refers to natural stone including igneous, sedimentary, and metamorphic rocks in solid form without cracks.

Article 3. Explanation of Terms

In this Circular, the following terms shall be understood as follows:

Block stone used for tiling (hereinafter referred to as tiling stone) is a stone block with a volume of 0.4 cubic meters or more, used in its original form or processed into sheets for decoration, tiling, and paving.

Block stone used for sculpture (hereinafter referred to as sculptural stone) is a stone block with a volume of 0.1 cubic meters or more, used in its original form or processed and crafted into artistic products.

Fracturing degree is the extent of development of natural cracks in the rock forming similar crack systems, reducing the integrity of the rock.³Distance between cracks (denoted as

) within the same crack system is the distance between two adjacent cracks with similar orientations.

Article 4. Classification of Reserves, Resource Grades, and Requirements for Reserves and Resource Blocks lThe classification of reserves, resources, and requirements for reserves and resource blocks of tiling stones and sculptural stones shall be carried out in accordance with the provisions of Circular No. 60/2017/TT-MT dated December 8, 2017, issued by the Minister of Natural Resources and Environment on the classification of reserves and mineral resources (hereinafter referred to as Circular No. 60/2017/TT-MT), specifically:

1. Criteria for classifying reserves and resource grades of tiling stones and sculptural stones: carried out in accordance with Article 5 of Circular No. 60/2017/TT-MT.

2. Reserve and resource grades of tiling stones and sculptural stones: carried out in accordance with Article 6 of Circular No. 60/2017/TT-MT. 3. Requirements for the level of assessment and grouping of reserve and resource grades: carried out in accordance with Article 7 of Circular No. 60/2017/TT-MT.

1. The division of exploration mine groups is based on the complexity of geological structure of the mine; shape, size, stability of thickness, quality of rock, internal structure of the ore body, and quantitative indicators assessing the variability of other parameters.

2. Division of exploration mine groups:

a) Tiling stone mines are divided into three groups: Simple Mine Group (code I); Relatively Complex Mine Group (code II); Complex Mine Group (code III);

Article 5. Classification of exploration deposit groups

b) Sculptural stone mines are divided into four groups: Simple Mine Group (code I); Relatively Complex Mine Group (code II); Complex Mine Group (code III); Very Complex Mine Group (code IV).

1. Exploration must follow the principle from general to detailed, network density from sparse to dense; each stage's work content must be fully implemented according to technical standards; the level of mine research must ensure sufficient data and materials to determine the quality, reserves, and exploitation potential of block stones used for tiling and sculpture, and meet environmental protection requirements as prescribed by law.

2. Design trial mining pits to collect information on weathering layer thickness, orientation factors of crack systems, integrity, recovery rate of different grade blocks, take samples for researching decorative properties, processing technology of tiling stones, and final product yield ratio.

Trial mining pits must represent the exploration area. The maximum volume of trial mining pits is 100 cubic meters per pit (for tiling stones) and 50 cubic meters per pit (for sculptural stones), excluding overburden and weathered rock layers.

3. The classification of exploration deposit groups as stipulated in Clause 2 of this Article shall be implemented in accordance with Appendix 1 issued together with this Circular.

Article 6. Requirements for exploration work

The number of trial mining pits designed for one exploration project is a maximum of three pits, subject to review and decision by the competent state authority.

3. Collect all geological data and other relevant materials to ensure sufficient basis for designing exploitation. Collection is conducted in accordance with Circular No. 43/2016/TT-MT dated December 26, 2016, issued by the Minister of Natural Resources and Environment on technical regulations for collecting and establishing primary documents in basic geological surveys and mineral exploration.

4. Conduct exploration throughout the entire area covered by the exploration permit issued by the competent state management authority.³5. Exploration works for tiling stones and sculptural stones must ensure the following main contents:

a) Use drilling, excavation, surface cleaning, crack measurement, rolling station, and trial mining pits to assess recoverability, rock quality, and ore body delineation. Select appropriate exploration methods suitable for the ore body's orientation, structure, thickness, overburden characteristics, and surface topography;

b) Arrange exploration works to control the full thickness of the ore body or reach the planned mining depth within the exploration boundary;

c) The directional network of exploration works is carried out in accordance with Appendix 2 attached to this Circular;

d) Properly arrange the network of crack measurement stations to ensure comprehensive data collection for determining rock integrity. Conduct crack measurements on drilling platforms or near drill holes to combine surface and deep crack data. Do not measure cracks at blasting sites;

đ) The core sampling rate through the ore body must be at least 85%, and through interbedded or surrounding rock layers must be at least 80%;

e) Trial mining pits must be designed to comply with all provisions of Clause 2 of this Article.

c) Network of directional exploration works carried out in accordance with Appendix 2 attached to this Circular;

d) Properly arrange the network of crack measurement stations to ensure the collection of complete data for determining the rock mass integrity. Conduct crack measurements on the drilling platform or near the drill hole location to combine surface and deep crack treatment. Do not measure cracks at worksites where blasting has occurred;

đ) The core sampling rate through the ore body must be at least 85%, and through interbedded rock layers or surrounding rocks must be at least 80%;

e) The trial mining pit must be designed to fully comply with the provisions of Clause 2 of this Article;

Article 7. Requirements for Topographic Basis and Geodetic Work

1. The area of exploration must be depicted on topographic maps with corresponding scale requirements for exploration work. Topographic maps shall be established in accordance with current regulations on geodetic work in mineral exploration.

2. All exploration works must determine coordinates and elevations according to the National Coordinate Network as stipulated by current regulations.

3. The mine topography for exploration must be detailed at a scale > 1:2,000.

Article 8. Requirements for Geological Mapping

1. Geological mapping of the mining area must ensure the determination of geological structure characteristics, formation conditions, petrographic composition, and degree of alteration and development of cavities in the ore body, as well as the degree of fracturing and destruction of rocks. Structural geological maps of the mine at a scale of 1:2,000 (for facing stones) and 1:1,000 (for decorative stones) along with geological cross-sections must be established. Regional geological maps must be presented at a scale of 1:10,000 or larger based on the largest scale geological maps that have been surveyed.

2. The establishment of the maps specified in Clause 1 and Clause 2 of this Article shall be carried out in accordance with the national technical regulation QCVN 49:2012-BTNMT issued together with Circular No. 23/2012/TT-BTNMT dated December 28, 2012, by the Minister of Natural Resources and Environment regarding the national technical standards for establishing geological maps of minerals at a scale of 1:50,000 for land areas.

Article 9. Requirements for Hydrogeological and Engineering Geological Work

1. Hydrogeological assessment:

a) Collect hydrogeological data from the exploration area for at least the last five years at the time of exploration;

b) Exploration results must assess the main water-bearing layers that could cause flooding in the mine, especially in parts of the mine with high flood risk to address the issue of mine drainage;

In cases where the exploration area is adjacent to operating extraction sites with similar hydrogeological and engineering geological conditions, during the process of determining hydrogeological and engineering geological parameters, data on water levels, engineering geological conditions, and drainage measures applied at these extraction sites must be collected and utilized;

c) Research the chemical and microbiological components of water, evaluate the beneficial and harmful contents in water; assess the impact of mine dewatering on underground water and domestic water supply in the region. Recommend solutions for water supply and drainage and the extent of impact of mine drainage on the surrounding environment.

2. Engineering Geological Assessment:

a) Determine the physical and mechanical properties of rock masses and surrounding rocks under natural and water-saturated conditions; engineering geological features of soil and rock strata and their anisotropic characteristics (if any); rock and soil composition, fracturing, tectonic destruction, cavities; the degree of influence of weathering zones related to design;

b) Evaluate the stability of mine structures and calculate basic parameters of the open-pit mining area.

Article 10. Requirements for Quality Research Work

1. Sampling requirements:

All exploration works must take samples. Basic samples include: petrographic samples, chemical analysis samples, physical and mechanical property samples, polishing and grinding samples, and technological samples. Types and quantities of samples depend on research and design purposes specified in the exploration plan.

2. Requirements for Sample Analysis:

Determine parameters to assess the quality of rock blocks used for facing stones and decorative stones to guide reasonable usage. Basic parameters include: color, petrographic composition, chemical composition, beneficial and harmful components, physical and mechanical properties, and other factors depending on the type of mineral, purpose, and value of use (whiteness, gloss, transparency, decorative effect, etc.); the number and types of samples are determined specifically for each exploration project.

3. Requirements for Taking and Studying Technological Samples:

a) Assess the usability of rock blocks for facing stones and decorative stones and select processing and manufacturing techniques based on testing each type of technological sample according to its intended use;

b) Technological test samples must be representative, having petrographic and mineralogical compositions and physical and mechanical properties typical of the entire exploration area;

c) For rocks that do not meet storage criteria, including those in overburden layers, the potential for alternative uses must be evaluated.

4. Requirements for Mine Quality Assessment:

The quality and value of rock blocks used for facing stones and decorative stones in the mine must be assessed and compared with those of other operating mines or existing products of the same type on the market.

Article 11. Requirements for technical exploitation condition research work

1. Preliminarily determine the boundaries of the mining area, the slope angle of the layer's side, the final extraction pit slope angle, stripping ratio and volume of overburden, and the location of waste dump sites.

2. Clearly define the boundaries of areas not containing stone blocks used for tiling and decorative purposes; propose measures to protect mineral resources and the environment.

Article 12. Requirements for reserve and resource calculation work

1. Prepare maps, cross-sections, and models of ore bodies that fully reflect the information from exploration results to calculate reserves and resources.

2. Reserves and resources of stone blocks used for tiling and decorative purposes and stones that do not meet accompanying standards shall be calculated using either the vertical parallel section method, the contour line method, or the geological block method. Priority should be given to using computer software to model blocks for calculating reserves and resources.

3. The unit for calculating reserves and resources of stone blocks used for tiling and decorative purposes, stones that do not meet accompanying standards, and stripped stones is m³.³.

Article 13. Requirements for the highest reserve level and the proportion of various reserve levels

1. For mines belonging to Group I and Group II, the highest level of reserves explored is Level 121. For mines belonging to Group III and Group IV, the level of reserves explored is Level 122.

2. The quantity and ratio between Levels 121 and 122 reserves must be determined based on the mine's geological characteristics, financial capacity, technical conditions for exploitation, and designed exploitation capacity but must ensure that the ratio of Level 121 reserves to the total of Level 121 and 122 reserves is ≥ 15% (121/(121+122) ≥ 15%) or sufficient for the designed exploitation plan within five years.

3. The quantity, ratio of reserve levels, and the exploitation period specified in Clause 2 of this Article must be specifically reflected in the exploration project.

Article 14. Content and form of documents in the exploration report

The content and format of documents in the exploration report for tiling stones and decorative stones shall be implemented according to the provisions of Circular No. 45/2016/TT-BTNMT dated December 26, 2016, issued by the Minister of Natural Resources and Environment regarding exploration plans, closure of mineral mines, and sample reports on mineral activities, sample documents in the permit application dossier for mineral activities, and the approval dossier for mineral reserves; procedures and formalities for closing mineral mines.

Article 15. Transitional Provisions

1. Organizations and individuals who have been granted permits for exploring stone blocks used for tiling and decorative purposes before this Circular takes effect shall continue to implement according to the laws in force at the time of granting the exploration permit.

2. Exploration projects for stone blocks used for tiling and decorative purposes that have been accepted by competent state authorities before this Circular takes effect but have not yet been reviewed and granted exploration permits shall continue to be implemented according to the laws in force at the time of acceptance.

Article 16. Effectiveness and Implementation

1. This Circular takes effect from October 20, 2020. In cases where referenced legal documents for application in this Circular are amended, supplemented, or replaced, implementation shall be carried out according to the provisions of the amended, supplemented, or replaced document.

2. The Director of the Vietnam General Department of Geology and Mineral Resources and the Head of the Office of the National Mineral Reserve Evaluation Council are responsible for guiding and inspecting the implementation of this Circular.

3. Ministries, agencies equivalent to ministries, government agencies, provincial People's Committees under central cities, and related organizations and individuals are responsible for implementing this Circular./.

ANNEX 1. CLASSIFICATION OF EXPLORATION MINES

(Annexed to Circular No. /2020/TT-BTNMT dated month day year 2020 issued by the Minister of Natural Resources and Environment)

1. Simple Mine Group (Code I):

1. Fracturing degree: has 2 or 3 main fracture systems, with more than 30% of the distance between parallel fractures exceeding l < 5m. More than 50% of core samples drilled through the product layer, with a length greater than 1m.

2. Large and medium-sized mines with simple geological structure; stone block storage coefficient greater than 0.3; cave and cavity storage coefficient (for carbonate and basalt rocks) less than 10%; thickness variation coefficient (Vm for metamorphic rocks) less than 40%.

1. Relatively Complex Mine Group (Code II):

1. Fracturing degree: has 3 main fracture systems and minor fractures,

with more than 30% of the distance between parallel fractures being l < 2.5m.

More than 30% of drill cores through the product layer, with a length greater than 1m.

1. Large and medium-sized mines with complex geological structures; stone block storage coefficient greater than 0.2 for tiling stones, greater than 0.1 for decorative stones; or cave and cavity storage coefficient (for carbonate and basalt rocks) greater than 10%; thickness variation coefficient (Vm for metamorphic rocks) less than 60%.

larger than 0.2 for facing stone, larger than 0.1 for decorative stone; or coefficient

containing cavities, hollows (for carbonate, basalt rocks) greater than 10%; thickness variation coefficient (Vm for metamorphic rocks) less than 60%.

1. Complex Mine Group (Code III):

1. Fracturing degree: has 3 main fracture systems and minor fracture systems, with more than 30% of the distance between parallel fractures being

2. < 1.25m. More than 10% of drill cores through the product layer, with a length greater than 1m.

1. Medium and small mines with complex to very complex geological structures; stone product storage coefficient greater than 0.1 for tiling stones, greater than 0.05 for decorative stones; or cave and cavity storage coefficient (for carbonate and basalt rocks) greater than 15%; thickness variation coefficient (Vm for metamorphic rocks) less than 80%.

1. Very Complex Mine Group (Code IV): l Fracturing degree: has 3 main fracture systems and minor fracture systems, with more than 30% of the distance between parallel fractures being

2. < 0.7m. No drill cores longer than 1m through the product layer.

ANNEX 2

Mines with very complex geological structures; stone product storage coefficient greater than 0.02; or cave and cavity storage coefficient (for carbonate and basalt rocks) greater than 15%; thickness variation coefficient (Vm for metamorphic rocks) greater than 80%.

NETWORK OF ORIENTATION FOR MINING WORKS TO EXPLORE STONE BLOCKS USED FOR TILING AND DECORATIVE PURPOSES

Note: 1. The network of orientation works for exploration is not mandatory in all cases. Based on a thorough analysis of the geological structure characteristics of the mine; shape, size, and position of the ore body; topographical features, patterns, and degree of variation in thickness and quality, the most appropriate network of exploration works for the exploration target is selected. Specifically, for decorative stone, if the classification criteria for mine groups meet the requirements of Group II mines, then the network of works for calculating reserves at level 122 is applied similarly to the network of works for calculating reserves at level 121 for facing stones.

2. The group of mines for exploration proposed in the exploration project may be adjusted during the implementation of the project to suit actual conditions.