Complex sentence: During 1989 a utilities contractor unexpectedly broke through into part of the mines complex whilst excavating a trench, which raised concerns locally which resulted in the then Bath City Council commissioning studies to survey the condition of the mines.
Split into simpler sentences: During 1989 a utilities contractor unexpectedly broke through into part of the mines complex whilst excavating a trench. This raised concerns locally, resulting in the then Bath City Council commissioning studies to survey the condition of the mines.