Complex sentence: In the 1930s, a dance hall and canteen were built but unfortunately, over time, the Silver Sands Beach, was being destroyed by the removal of sand for construction of the container piers in Halifax Harbour and to build the runway at CFB Shearwater Airport.
Split into simpler sentences: In the 1930s, a dance hall and canteen were built but unfortunately, over time, the Silver Sands Beach, was being destroyed. Sand was being removed for the construction of the container piers in Halifax Harbour and to build the runway at CFB Shearwater Airport.