Reports of Research on Pennsylvania’s Coal Resources
These reports were completed by the Mineral Industries Experiment Station from 1957 to 1972. The interim progress reports (IPRs), comprising thirteen or more programs of research, are concise statements of progress issued at six month intervals. These are compiled and issued as part of the working reports. As work is completed in each program area, a special report will be issued (see Coal Research Board Special Research Reports).
| IPR-1 | April 15, 1957 - August 1957 |
| IPR-3 | March - August 1958 |
| IPR-19 | January - June 1966 |
| IPR-20 | July - December 1966 |
| IPR-27 | 1970 |
| IPR-28 | 1971 |
| IPR-30A | July - December 1971 |
| IPR-31B | January - June 1972 |
| No. 1 | April 15, 1957 - August 1957 |
| No. 2 | September 1957 - February 1958 |
| No. 4 | September 1958 - February 1959 |
| No. 5 | March - September 1, 1959 |
| No. 7 | March - August 1960 |
| No. 8 | September 1960 - February 1961 |