Measurement of total core recovery; dealing with core loss and gain

Abstract: The measurement of total core recovery is apparently a simple measurement to make and so there is little guidance available on how to actually carry this out. As core drilling is carried out in an increasingly wide range of materials, the difficulties in recording this simple index also increase. This technical note sets down some of the procedures that need to be followed for efficient and accurate record taking. The logging of rotary drill cores requires that the total core recovery (TCR) is measured to provide a record of the proportion of core recovered. Although this index gives little information on the character of the material its measurement is required in the logging of cores recovered from rocks, soils and made ground such as concrete and brickwork. There are a number of practical difficulties in recording the TCR whenever the recovery is not 100%, a situation that has increased in frequency with the use of rotary coring methods in an increasingl