MT/T 1090-2008Evaluation of Coal Quality in Coal Resource Exploration (English PDF)

3.2 Coal quality work in the reconnaissance stage

Generally-understand the general characteristics of coal types and coal quality; study the original materials of coal, coal rock composition, as well as types of coal formation;

study the coal quality characteristics of each major coal seam, its changing law, and the changing rules of major harmful components in coal; preliminarily analyze the coal metamorphic factors. Sampling types, quantities, and test items can refer to Tables A.1 and A.2 in Appendix A.

3.3 Coal quality work in the prospecting stage

Roughly-determine the characteristics of coal types and coal quality in the mineable coal seam; study the original materials of coal, coal rock composition, as well as types of coal formation; study the coal quality characteristics of each major coal seam, its changing law, and the changing rules of major harmful components in coal; further analyze the metamorphic factors in each major coal seam. Sampling types, quantities, and test items can refer to Tables A.1 and A.2 in Appendix A.

3.4 Coal quality work in general exploration stage

Basically-identify the coal quality characteristics and process performance of the mineable coal seam; determine the coal types of the mineable coal seam; evaluate the industrial utilization direction of coal; preliminarily identify the weathering zone boundary of the major mineable coal seam; evaluate the degree of change of the coal quality of coal seam; comprehensively study the physical and chemical characteristics and changing law of each mineable coal seam; study the coal distribution law; make a preliminary evaluation of the comprehensive utilization direction of coal and its impact on the coal seam mining. The sampling types, quantities and test items can refer to

Tables A.1, A.2, and A.3 in Appendix A.

3.5 Coal quality work in detailed exploration stage

Find out in detail the characteristics of coal types and coal quality of mineable coal seam, and their changes within the pre-mined area. According to the requirements of development and construction, focus on studying the coal quality characteristics and process performance related to the mining, washing, processing, sales, environmental protection, utilization, etc. of the coal; and make corresponding evaluation. The sampling types, quantities, and test items can refer to Appendix A, and Tables A.1, A.2, and A.3.

4.2.2 The coal sample of coal core is generally taken as full-layer sample based on the independent coal seam. When the coal quality is significantly different and the layer thickness is greater than 0.5m, then take the stratified coal sample. When sampling from the coal seam with complex structures, it shall be taken separately according to the gangue and coal stratification.

4.2.3 The gangue larger than 0.01m to the minimum mineable thickness of coal seam shall be sampled separately. For the gangue greater than the minimum mineable thickness of coal seam, if it belongs to non-carbonaceous mudstones, it shall not be sampled; if it belongs to carbonaceous mudstones or soft rocks, it shall be sampled separately. The gangue with thickness less than or equal to 0.01m, it shall be sampled together with the connected coal layer rather than be removed. The gangue of multiple thin coal seam can be sampled separately, or combined with the same lithology to be sampled.

4.2.4 When the false top and false bottom of the coal seam are carbonaceous mudstones, full-layer samples shall be taken separately. If it belongs to the non- carbonaceous mudstone, the layer thickness is greater than 0.1m, take sample of 0.1m;

if the layer thickness is less than 0.1m, all shall be sampled.

4.2.5 The coal sample of coal core needs to be sampled according to different coal seams without shrinkage. When the coal seam thickness is large, it shall be sampled in sections. The section thickness is generally no greater than 3.0m; the interval of steeply inclined coal seams can be appropriately relaxed.

4.2.6 When taking out the coal core from the borehole to the end of the sampling, it shall not exceed 8h for lignite, not exceed 24h for bituminous coal, and not exceed 48h for anthracite. The mass of the coal sample of coal core shall be at least 1.5kg. If special items of test are required, the number of samples can be determined according to the test requirements.

4.3 Coal sample for testing washability

4.3.1 The coal sample for testing washability can be divided into two types including size and float-sink test coal sample (also known as production sample), and coal sample for testing washability of coal core coal sample (also known as simple sample).

4.3.2 The size and float-sink test coal sample shall be taken in the production mines or exploration tunnels with a mass of no less than 10t. The sampling points shall be arranged below the oxidized zone and in areas with normal coal seam thickness, structure, and coal quality. Detailed geological records shall be made near the sampling points. The coal sample shall include the mined gangues and naturally mixed false top and false bottom vermiculite. Except where stratified sampling is required, full-layer sampling is generally adopted. When taking all the coal from the coal seam roof and floor in the sampling laneway, if the amount of mined coal is too large, it can of the sample groove; calculate its volume. Use the same method to calculate the volume of gangue (if the gangue shape is irregular, immerse it into the water to measure its volume) with thickness greater than 0.05m. Accurately measure the mass of all coal samples in the dry-air state; shrink a sample to determine the moisture, ash, true density and apparent density, etc. Two volume and mass coal samples with similar specifications shall be taken from the same sampling point; their measurement results difference shall be no greater than 0.05t/m3. It the above value is exceeded, take a third sample.

4.4.3 When taking full-moisture coal sample int eh tunnel, select the fresh coal surfaces with no water dropping and normal temperature to take according to the requirements;

or use the size and float-sink coal sample and production coal sample to shrink by quarter method. Place the coal sample with particle size less than 13mm and mass no less than 2kg into ground-mouth sample bottle (the sample volume shall not exceed

3/4 of the volume of the coal sample bottle). The coal sample shrinkage, shipping into bottle must be finished as quickly as possible in the sampling location, then immediately sealed by the black tape, sealed by wax after transferring into the room.

Wipe the container surface, weigh it accurately (use a tray balance with sensitivity of

0.1g); label it properly; send it to the laboratory within 5d.

4.5 Coal sample of coal rock

4.5.1 For the coal sample of coal rock that reflects normal coal quality, its sampling points shall avoid the abnormal zones such as fracture zone, wind-oxidization zone, magmatite contact zone, spontaneous combustion metamorphic zone, etc. The coal sample of coal rock with special research purposes needs to be taken at specific location.

4.5.2 When sampling, the following contents shall be described in detail, such as coal seam structure of the sampling point, physical properties of coal, macro coal type, top and bottom lithology, nearby structural characteristics.

4.5.3 The coal sample of coal rock can be divided into mixed coal sample, columnar coal sample, and lump coal sample. The mixed coal sample can be shrunk from coal sample of coal seam, coal sample of coal core, and coal sample of washability. The columnar coal sample can be taken from the trenches and tunnels; the well-structured columnar coal core can be used as the columnar coal rock sample. When the coal quality is hard, the continuous lump coal samples can be used instead of columnar coal sample. If the coal core and coal seam in the tunnel are not suitable for taking the columnar coal sample, discontinuous lump coal can be picked as coal sample of coal rock.

4.6 Coal sample of spore and pollen

4.6.1 The coal samples of spore and pollen for the different research purposes shall method (while-lane method, pumping method, interception method on the belt conveyor, etc.); lithology of false top, false bottom and gangue; thickness; mixing condition of waste rock and whether there are people to pick them by hand, etc.

5.3 Storage of coal sample

The exploration organization generally does not keep the retained samples. The following coal samples, such as coal sample of coal seam, coal sample of coal core, coal sample of coal rock, coal sample of spore and pollen, etc., shall be kept by the testing organization for analysis samples (or briquettes). The testing organization shall take certain measures to prevent the oxidization of the coal samples. The storage time is generally half a year since the date of test results are reported, namely, after the quality review of test item involved in the sample is completed. If there is agreed storage time, it shall be abided by.

6.1 Sample treatment

After receiving the coal sample, the testing organization shall check the sample in time.

If the coal sample instructions are inconsistent with the coal sample number label, immediately send it to the inspection organization for checking. After confirming no error, the delivered sample shall be successively classified, numbered with password;

and the sample shall be pre-processed, shrunk, prepared sample according to the corresponding technical specifications; then hand them over to the test personnel for indoor testing.

6.2 Sample test

The test personnel shall firstly check the sample password; then test according to the corresponding test specifications. The operation process shall be strict and regulated.

The original records shall be true and reliable. The test report shall be scientific and true. If the test results deviate due to the quantity and quality of delivered sample, test environment, and other factors, it shall be noted in the test report.

6.3 External inspection test

When testing the sample, the external inspection comparison test shall be carried out;

the quantity of external inspection shall be no less than 1%.

6.4 Gangue sample

The gangue or top and bottom waste rock sample shall be conducted industrial analysis and full-sulfur analysis; meanwhile increase the measurements of calorific value, true relative density, trace elements, harmful compositions, ash compositions, provisions of MT/T 561.

7.2.6 Yield of volatile matter of coal

The quality classification of yield of volatile matter of coal shall be carried out as per the provisions of MT/T 849.

7.2.7 Coal ash fusibility

The coal ash fusibility is an important quality parameter for evaluating the coal used for drive and gasification. Generally, 4 temperatures are used to evaluate the coal ash fusibility: deformation temperature, softening temperature, hemisphere temperature, and flow temperature. The quality classification of softening temperature of coal ash fusibility shall be carried out as per the provisions of MT/T 853.1; while the quality classification of flow temperature of coal ash fusibility shall be carried out as per the provisions of MT/T 853.2.

7.2.8 Thermal stability of coal

The thermal stability of coal indicates the degree of thermal stability of coal during the high-temperature combustion or gasification of coal; its quality classification shall be carried out as per the provisions of MT/T 560.

7.2.9 Hardgrove grindability index of coal

The hardgrove grindability index of coal is of great significance for designing and reforming pulverized coal preparation system, calculating the yield and power consumption of the coal mills. The quality classification of hardgrove grindability index of coal shall be carried out as per the provisions of MT/T 852.

7.2.10 Caking index of bituminous coal

The caking index is an important indicator for evaluating the caking and coking properties of coal. The major use of coal can be roughly determined by the caking index of the coal. The quality classification of caking index of bituminous coal shall be carried out as per the provisions of MT/T 596.

7.2.11 Harmful compositions in coal

Harmful compositions in the coal, such as fluorine, chlorine, phosphorus, arsenic, lead and mercury, have a great impact on the processing and utilization of the coal.

The quality classification of fluorine in coal shall be carried out as per the provisions of

MT/T 966.

The quality classification of chlorine in coal shall be carried out as per the provisions of GB/T 20475.2.

(%) < 80, it indicates the coal has been oxidized, such coal may cause deterioration of coke quality and coking operation problems. It shall be carried out specially as per the provisions of GB/T 19224.

7.2.17 Radioactivity of coal

The fly ash and coal gangue formed from the processing and utilization of the coal are important industrial and construction raw materials. Its radioactive pollution may cause different degrees of damage to the human. The quality classification of the radioactivity of coal shall be carried out as per the provisions of GB 6566.

7.3 Evaluation of coal quality use

7.3.1 Coal quality evaluation index of coal used for drive

From the perspective of coal resource geological evaluation, comprehensively consider the impact of various coal quality indexes on the equipment with coal as fuel, and refer to the relevant national standards. The coal quality evaluation indexes of the coal used for drive mainly include moisture, calorific value, volatile matter, ash, sulfur, ash fusibility, slagging, caking index, coking, grindability, particle size, and trace elements in the coal.

7.3.2 Coal quality evaluation indexes of coking coal

The geological evaluation of coking coal resources is mainly based on the specific characteristics of unsorted raw coal and the specific conditions of the coal quality test indicators in the existing coal quality data. The coal quality evaluation indexes of coking coal mainly include maximum reflectance of vitrinite, volatile matter, sulfur, ash, caking and coking, microscopic coal rock composition, total moisture, phosphorus, ash composition, ash fusibility, washability of coal.

7.3.3 Coal quality evaluation index of coal for gasification

The coal quality is the basis for selecting a gasification method; it is the key to affecting the technical and economic indicators of the gasification process and its smooth operation. A gasification method can only give full play to its efficiency by choosing the right coal type. The coal quality evaluation indexes of coal for gasification mainly include moisture, ash, volatile matter, sulfur, fixed carbon, total moisture, calorific value, ash fusibility, maximum thickness of colloidal layer, lower limit rate, gangue rate, caking property, chemical reactivity of coal towards the carbon dioxide, thermal stability, crushing resistance strength, particle size, harmful component contents.

7.3.4 Coal quality evaluation index of liquefication coal

Selecting coal with good liquefication performance can not only get high conversion and oil yield, but also can reduce the operating costs and production costs. The coal slagging and tar yield, etc. in the mineable coal seam.

Insert the corresponding chart as describe the text.

8.1.5 Washability of coal

Describe and evaluate the washability test results of the coal.

Insert the corresponding chart as describe the text.

8.1.6 Coal types

Describe the coal types of each mineable coal seam and its basis of determination;

describe the distribution range of each coal seam, and each coal type; determine the method and reliability for the changing boundary of the coal type. According to the following factors such as the thickness of coal-bearing strata and overlying strata, the modern burial depth of coal seam, whether there is magmatic activity in the and nearby the area, and the influence of tectonic stress caused by folds and fracture of the coal strata on the coal seams, etc., discuss the coal metamorphic factors and classify the coal metamorphic types.

The main and auxiliary indexes for the industrial classification of coal shall be strictly identified. The abnormal values, combined with the chemical, coal rock components, and mutual relationships among the indexes, shall be analyzed carefully, then trade- off them.

8.1.7 Weathering and oxidation of coal

Describe the method of determining the weathering and oxidation zone of coal; the characteristics of coal in weathering and oxidation zone; and the distribution range of weathering and oxidization zone of coal. Evaluate the possibility of utilization of coal in weathering and oxidization zone.

Describe the spontaneous combustion tendency of coal seam, and the influence of spontaneous combustion of coal seam on the coal seam and coal quality. Evaluate the coal quality characteristics and possible uses of the burning residual coal.

8.1.8 Coal dust explosion

Describe the test results of coal dust explosion.

Describe the relevant information of the coal dust in the well fields, neighboring mines and small coal mines.

Evaluate the coal dust explosion in the well fields.

8.1.9 Spontaneous combustion tendency of coal

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