Final answer:
Cape Breton Island is principally known for its history of coal mining, which played a major role in the island's economy.
Step-by-step explanation:
Cape Breton Island is famous for coal mining. Historically, coal was the primary mineral resource extracted from the island, significantly contributing to the local economy. While other places in Canada are known for different types of mining, such as diamond mines in the Canadian Shield and metallic ores like copper and gold, Cape Breton's mining heritage is predominately associated with coal, particularly from the Sydney Coal Field.