The coal strength obtained in this research work from the relationship between the perpendicular PLT and SDI data from cycles 2-5 has the highest accuracy and reliability among all the presented mechanical properties. Next, the importance of conducting this study and the potential implications of the findings of this research project are briefly discussed.
Statement of problem
In this chapter and the following sub-sections, first, a brief description of slag sustainability is given, then the research problem statement and research questions addressed in this research project are presented. This is followed by explanations of the research methodology designed to achieve the relevant research objectives.
Relevance to industry
Aims and objectives
Research methodology
Thesis organization
This chapter presents an overview of the data source and structure of the coal mining industry in the world and particularly in Kazakhstan.
Coal reserves and production
The coal mining industry in Kazakhstan
The input data of this project are the results of geological surveys on the entire territory of the country. Contract territories in the Republic of Kazakhstan for the production of hydrocarbons and coal (map, 2018).
Study area and geology
Because one of the competitive and fast-growing sectors of Kazakhstan's mining industry attracts foreign investors. For the tests, coal samples are collected at seven locations from currently under construction coal seams (4) and mines (5).
Classification of coal
Due to the general data obtained from coal seams, coal grade “KZh” was selected for investigation and for comparison of the effect of quality on the samples of the result location, K12K was added. Thus, coal samples from the K7 and K12 layers of the Saranskaya Coal Mine were not included for the further studies, as well as the Lenina mine, but the latter because sufficient samples were obtained from the corresponding layer D6.
Slake durability
Strength of coal
The study by Pan et al. 2013) reveals how coal microstructures affect coal mechanical properties, mainly UCS and Young's modulus. As can be seen from Figure 4, UCS and Young's modulus are affected by the physical and chemical properties of coal.
Physical properties of coal
Density
ARD is a ratio of the mass of dry coal to the mass of a volume of water equal to the apparent volume of the coal at a specified temperature.” The bulk density (BD) is the ratio of total mass to the volume occupied by coal. For the same coal sample, the values of the BD are less than the value of ARD and the value of TRD is the highest.
Coal surface area and porosity
Since the results of volume are more accurate when the liquid grows the ability to mold tightly into the surface pore of the sample, Crawford (2013) suggests using the adult immersion method. Review of the previous works regarding the palatability test and relating them to coal.
Hypothesis
To achieve the goals and objectives of this research, the scope of work must be planned. A planned project plan assigns tasks and activities, so to execute them accordingly, risk management and a contingency plan were applied.
Tasks and activities
Identification of standard test procedures performed on coal and requirements for the sample. Contact with AMT company for mine visit, collection of coal samples from KCB for laboratory testing;.
Research plan
Equipment and material requirements
The university laboratory has the necessary testing equipment; The installation and its components must be in place. Density, creep stability test Scale, hammer, furnace, container Pore structure Nitrogen Uniaxial compressive strength pore gauge.
Other required resources for research
Most importantly, samples for conducting laboratory tests at the university must be properly stored once retrieved from the mine.
Project plan
Planning the specimen preparation
This research project aims to evaluate the physico-mechanical properties of intact rock and the correlation of quenching durability with the density, uniaxial compressive strength (UCS), Point Load Index (𝐼s (50) ), porosity (n). To describe the sizing of coal samples for each procedure according to the number of tests and sample geometry, the diagram shown in Figure 6 has been prepared.
Planning the testing procedures
Planning the data analysis
Project schedule
Collection of samples that meet specifications 2.3 Sample preparation and equipment setup 2.4 Performance of laboratory tests.
Risk assessment
This method of risk analysis can help to identify which of the following actions should be implemented, or to conduct further risk analysis or to find an answer. From the design risk category, design errors and omissions that mean the lack of a design step(s) parameter (D1) have a high degree of impact on the duration of the overall research project. According to the project management risk category, the issue of misconduct due to inappropriate referencing of material (eg plagiarism) (PM2) has a high impact on the delivery of high-quality work.
E1 Remarks from the company appear by requesting some adjustments 1 2 Low E2 Unavailability of laboratory or test equipment 3 4 Significant.
Risk management plan
PM1 Failure to meet the quality requirements of project delivery 3 2 Moderate PM2 Misconduct: improper reference of the material, plagiarism 4 4 Extreme PM3 Conflict between company and student, or supervisor and student 1 3 Low. In such cases, processes will be executed before the current one by using the loop to make an iterative procedure. From the risk value with extreme risk category, the project management problem related misconduct issue due to improper referencing of the material (i.e. plagiarism) (PM2) has a great impact on the submission of high quality work.
The experimental part of the research is structured with the specification of testing equipment and existing methods of standardized testing procedures.
Sample selection
Specimen collection
For sample handling, transport and storage processes, these are important parameters to consider: the source of samples, sampling date, method of preserving samples during transport and storage.
Specimen preparation
Preparation of coal specimens for physical tests
Preparation of coal specimens for mechanical tests
The flushing speed affects the penetration speed; 16 litres/min is the optimum rate until the penetration rate then increases as the flushing fluid speed decreases (Singh and Ghose, 2006). However, this method of securing the sample securely for safe working conditions can add additional strength to the sample. The coal surface placed on the testing device is inked with a white correction marker; this is the same procedure common for both cubic and core samples, as shown in Figure 11a and Figure 11b, respectively.
The samples are finally ready for testing with a careful examination of the sample under the template, all that remains is the matter of proper labeling.
Test methods
- Slake durability
- Density
- Porosity
- Uniaxial compressive strength
- Point load test
Density of substance is a measure of mass per volume as shown by equation 2. 𝜌𝐶 = 𝑚𝐶/𝑉 2). The dry unit weight and effective porosity of the coal samples are determined using the automated gas sorption analyzer. The uniaxial compressive strength (UCS) of the specimen is the load carried by the specimen before failure at the original cross-sectional area as calculated by Equation 7.
The 𝐼s (50) of the specimens were determined by mounting each specimen between two plates on a point load tester to be tested under the same loading conditions.
Test procedures
- Determining 𝑰𝒅(𝑵) from slake durability test
- Determining 𝝆𝑪 from wax immersion density test
- Determining 𝝈 from Uniaxial Compressive Strength test
- Determining 𝑰 𝒔 (𝟓𝟎) from Point Load Test
Remove the drum with the preserved part of the coal samples and place it in the oven for 6 hours. When you have achieved a coating of the pattern with no air bubbles trapped in the wax, remove the pattern from the wax and allow the wax to harden;. Ensure perpendicularity to the axis of the sample and flatness (see the previous subsection);
The experiments carried out in the course of this research work included tests to determine the physical properties of the coal samples, such as porosity and bulk density.
Results
- Slake durability test
- Bulk density
- Porosity
- Uniaxial compressive strength
- Point load test
Descriptive statistics results of the SDT of three tests for each location are shown in Table 12. Some of the tests were performed with a loading direction perpendicular and some parallel to the coal seam bed or stratification. This is why it was not possible to obtain cores for the majority of the coal seams tested.
Again, some tests were carried out with a loading condition perpendicular and also parallel to the bottom plane to determine the anisotropy of the strength, if any.
Discussion
- Slake durability test
- Density
- Porosity
- Uniaxial Compressive Strength
- Point Load Test
The SDI values for cycles 2, 3, 4 and 5 are plotted against the corresponding SDI values of the first cycle presented in Figure 20. Here we can conclude that for the study coal samples there is a strong correlation between the SDI values from cycles 2-5 in compared to SDI values from cycles 2-5 compared to SDI values from cycle 1 SDI values for the tested coal samples.
An attempt is made here to establish correlations between the SDI values from cycles 2-5 obtained for the tested coal sample and UCS test data.
Summary of results and discussions
As can be seen from Figure 27, there is a weak to moderate and positive correlation between the PLI parallel versus the SDI values for cycles 2-5. As can be seen from Table 26, the correlation between the SDI values obtained from cycles 2-5 and the PLT perpendicularly is very strong. Considering that the UCS discussed in this study is also measured in the direction perpendicular to the bedding plane, this indicates that there is also a good correlation between UCS and PLI.
It was evaluated after which cycle of SDI the increment of r value between the strength properties (such as UCS and PLI) and durability indices after spreading does not change significantly.
Conclusions
There is a weak to moderate and positive correlations between the PLI parallel versus SDI values for cycles 2-5. Correlation coefficients between SDI and strength properties after the 4th cycle show more constant values. As a result of this research, it is found that the SDI of coal should be performed at least four cycles, which gives better result and correlation coefficients to compare the SDI with other coal properties.
However, these obtained results are valid for some sites from the Karaganda coal basin and should be used with caution.
Recommendations
In International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (Vol. 16, No. 2, pp. 138-140). Available at:
Determination of rock strength from scour durability tests, protodyakonov impact tests and los angeles abrasion resistance tests (Doctoral dissertation).
Listing of test data
Samples during tests
