*4.1. Determination of the Value of Parameter fC*

The value of the uniaxial compressive strength parameter *fC* was obtained through a uniaxial compression test. Five uniaxial compression tests were carried out, and three sets of effective data were obtained. Based on the obtained data, the stress–strain curves of briquette samples under uniaxial compression were plotted. The curves are shown in Figure 5.

**Figure 5.** Uniaxial compression stress–strain curve.

As shown in Table 4, the value of the uniaxial compressive strength parameter *fC* of the sample was obtained from the peak point of the stress–strain curve.


**Table 4.** Uniaxial compression test results.

According to the experimental results presented in Table 4, the mean value of the three samples was considered as the value of uniaxial compressive strength parameter *fC* for the briquette sample, which was 2.33 MPa.

### *4.2. Determination of the Value of Parameter T*

A splitting test was required to obtain the value of the uniaxial tensile strength parameter *T*. The test equipment used for the splitting of coal samples was the same as that used for the uniaxial compression test. Samples were disc-shaped with a diameter of 50 mm and length of 25 mm. The axial load was applied by displacement control at a rate of 0.05 mm/min. When a crack appeared on the surface of the coal sample, the experiment was finished. Sample damage resulting from the four splitting experiments is shown in Figure 6.

**Figure 6.** Splitting test specimen failure morphologies.

The load *P* at the failure point of the sample was obtained from the splitting test, and the tensile strength *T* of the sample was calculated using the equation *T* = 2*P*/π*dh*, where *d* and *h* are the diameter and length of the sample, respectively. The values of load *P* and tensile strength *T* at the fracture points of different samples are summarized in Table 5.


**Table 5.** Sample tensile strength values.

According to experimental results presented in Table 5, the mean value of the four samples was considered as the tensile strength of briquette sample, which was 0.55 MPa.
