Part of Oral Answers to Questions — Coal Industry. – in the House of Commons on 6th December 1938.
Following is the reply:
| South Wales and Monmouthshire. | ||||
| Year. | Number of Coal-cutting machines in use. | Number of Conveyors in use. | ||
| At the Coal Face. | Elsewhere below-ground. | |||
| 1920 | … | 239 | 339 | Not available. |
| 1921 | … | 273 | 342 | |
| 1922 | … | 304 | 416 | |
| 1923 | … | 361 | 562 | |
| 1924 | … | 409 | 671 | |
| 1925 | … | 405 | 721 | |
| 1926 | … | 401 | 740 | |
| 1927 | … | 425 | 697 | |
| 1928 | … | 401 | 581 | 191 |
| 1929 | … | 430 | 681 | 229 |
| 1930 | … | 460 | 745 | 228 |
| 1931 | … | 484 | 699 | 233 |
| 1932 | … | 437 | 653 | 222 |
| 1933 | … | 454 | 712 | 225 |
| 1934 | … | 472 | 727 | 239 |
| 1935 | … | 476 | 789 | 263 |
| 1936 | … | 482 | 785 | 278 |
| 1937 | … | 519 | 878 | 329 |
