Complex sentence: In 1868, he left for Rockhampton attracted by the opportunities of a new colony of Queensland, where he engaged in pastoral pursuits until 1871, but during these three years he took considerable interest in the copper mining in the Mackenzie district.
Split into simpler sentences: In 1868, he left for Rockhampton attracted by the opportunities of a new colony of Queensland, where he engaged in pastoral pursuits until 1871. During these three years, he took considerable interest in the copper mining in the Mackenzie district.