Table 1: Mean and standard deviation of total dust concentration (mg/m3) and silica content (mg/m3) of samples in different units of the studied silica mines.
| Unit
|
Dust
|
Mine 1
|
Mine 2
|
Mine 3
|
Mine 4
|
Mine 5
|
Mine 6
|
| Extraction |
Total |
15.3±2.8 |
16.2±3.9 |
16.2±2.7 |
16.2±2.1 |
12.9±3.2 |
18.2±3.8 |
| Silica content |
1.83±0.67 |
1.78±0.72 |
1.64±0.81 |
2.09±0.71 |
2.23±0.62 |
2.03±0.58 |
| Crushing |
Total |
18.2±3.8 |
18.7±3.9 |
19.2±4.1 |
17.2±3.2 |
20.2±4.2 |
19.7±3.2 |
| Silica content |
2.18±0.54 |
2.57±0.45 |
2.49±0.67 |
1.93±1.83 |
2.62±0.72 |
2.89±0.49 |
| Wet processing |
Total |
5.7±1.3 |
6.1±1.7 |
4.8±0.98 |
-* |
- |
- |
| Silica content |
0.79±0.48 |
0.854±0.39 |
0.816±0.54 |
- |
- |
- |
| Dry processing |
Total |
12.7±3.4 |
13.3±2.9 |
12.9±1.8 |
14.2±2.7 |
12.7±2.1 |
15.7±1.9 |
| Silica content |
1.89±0.78 |
1.98±0.68 |
2.19±0.42 |
2.14±0.54 |
2.03±0.62 |
2.13±0.58 |
| Loading |
Total |
11.3±2.9 |
10.9±2.1 |
11.8±3.1 |
12.2±2.2 |
11.5±1.9 |
9.8±2.1 |
| Silica content |
2.19±0.78 |
2.071±0.62 |
36.2±0.52 |
2.56±0.49 |
2.37±0.63 |
2.5±0.54 |
| Management/ administration |
Total |
3.1±0.9 |
4.1±1.3 |
2.8±0.9 |
3.2±0.98 |
3.8±0.78 |
2.9±0.74 |
| Silica content |
0.588±0.08 |
0.451±0.091 |
0.336±0.07 |
0.512±0.12 |
0.494±0.16 |
0.522±0.18 |
* Means have not been measured.