Table 1.
Comparison of several short-range wireless technologies.
| Technical standard | Bluetooth | Wi-Fi | Mobile communications | ZigBee |
|---|---|---|---|---|
| Working frequency | 2.4 GHz | 2.4 GHz | 0.8/0.9 GHz 1.8/1.9 GHz | 868 MHz/915 MHz/2.4 GHz |
| Coverage | 10 m | 100–200 m | Depends on network | 50–300 m |
| Transmission rate | 1 M/s | 11–54 M/s | 50k–2M | 10–250k |
| Power consumption | Big | Big | Small | Minimum |
| Cost | High | Low | Highest | Low |
| Delay | Short | Long | Shorter | Shorter |
| Confidentiality | Good | Better | Good | Good |
| Scalability | Difference | Good | Good | Good |
| Network capacity | Small | Big | Big | Big |
| Technical complexity | More complicated | Easy | Easy | Easy |
Figure 1:
Sketch map of mountain stope surveying layout.
Figure 2:
Flow chart of the ISL process.
Table 2.
Test sample water content test.
| Numbering | 1 | 1.39 | 3 |
|---|---|---|---|
| Aluminum box weight (g) | 17.05 | 2 | 17.56 |
| Box + wet soil mass (g) | 30.54 | 17.22 | 39.10 |
| Box + drying soil mass (g) | 30.34 | 30.54 | 38.82 |
| Mass of water (g) | 0.20 | 30.36 | 0.28 |
| Dry soil mass (g) | 13.29 | 0.18 | 21.26 |
| Moisture content (%) | 1.5 | 13.14 | 1.32 |
| Average moisture content (%) | 1.36 |
Table 3.
Comparison of the error between the actual water pressure value and the measured water pressure value.
| Sensor number | Measured water pressure (kPa) | Measured value of pore water pressure (kPa) | Measured accuracy (%) |
|---|---|---|---|
| 1# | 1.39 | 1.35 | −0.20 |
| 2# | 1.39 | 1.42 | +0.15 |
| 3# | 1.39 | 1.43 | +0.20 |
| 4# | 2.23 | 2.2 | −0.15 |
| 5# | 2.23 | 2.25 | +0.10 |
| 6# | 2.23 | 2.28 | +0.25 |
| 9# | 1.14 | 1.12 | −0.10 |
| 10# | 1.14 | 1.1 | −0.20 |
| 11# | 1.14 | 1.18 | +0.20 |
Figure 3:
Comparative analysis of the error between the actual water pressure value and the measured water pressure value.
Table 4.
Content of RE ions in the leaching solution of magnesium sulfate leaching in each time period.
| Leaching liquid | Leaching time/h | RE weight collected in leaching solution (mg) | ||
|---|---|---|---|---|
| A1 | B1 | C1 | ||
| Magnesium sulfate | 1 | 0 | 0 | 0 |
| 2 | 1.51 | 2.24 | 1.15 | |
| 3 | 8.54 | 10.76 | 7.56 | |
| 4 | 38.25 | 42.47 | 38.69 | |
| 5 | 10.58 | 12.01 | 15.28 | |
| 6 | 5.47 | 3.76 | 6.89 | |
| 7 | 0.78 | 0.66 | 0.45 | |
| 8 | 0.12 | 0.1 | 0.1 | |
Table 5.
Content of RE ions in the leaching solution of clear water leaching in each time period.
| Leaching liquid | Leaching time/h | RE weight collected in leaching solution (mg) | ||
|---|---|---|---|---|
| A2 | B2 | C2 | ||
| Shimizu | 1 | 0 | 0 | 0 |
| 2 | 0 | 0 | 0 | |
| 3 | 0 | 0 | 0 | |
| 4 | 0 | 0 | 0 | |
| 5 | 0 | 0 | 0 | |
| 6 | 0 | 0 | 0 | |
| 7 | 0 | 0 | 0 | |
| 8 | 0 | 0 | 0 | |
Figure 4:
Mass of RE precipitated in the leaching solution of the sample at each moment during the leaching process.