8. When a mine ceases to be open.

It is a question of degree whether a mine which has once been opened but which has not been worked for a time ceases to be an open mine1. Interruption of working for a moderate period will not necessarily be treated as evidence of abandonment so as to prevent the mine remaining open2. Nor will the cessation of working for a longer period where the cessation is due to an unremunerative market for the produce