Complex sentence: Within the parish bounds is some quarrying activity, extracting various grades of sand and gravel, however only two people were employed in mining and quarrying (0.2% of the working population)--the workings in the near northwest of the civil parish are dormant.
Split into simpler sentences: Within the parish bounds is some quarrying activity, extracting various grades of sand and gravel, however only two people were employed in mining and quarrying: 0.2% of the working population. The workings in the near northwest of the civil parish are dormant.