Question: what is the main industry in the canadian shield
[{'answer': 'mining', 'provenance': [{'wikipedia_id': '6230', 'title': 'Canadian Shield', 'start_paragraph_id': 1, 'start_character': 706, 'end_paragraph_id': 1, 'end_character': 712, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6230', 'title': 'Canadian Shield', 'start_paragraph_id': 20, 'start_character': 0, 'end_paragraph_id': 20, 'end_character': 676, 'bleu_score': 0.9825310706027971, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11479686214880095356}, 'section': 'Section::::Mining and economics.\n'}]}, {'provenance': [{'wikipedia_id': '6230', 'title': 'Canadian Shield', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11479686214880095356}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6230', 'title': 'Canadian Shield', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 725, 'bleu_score': 0.9530446225172671, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11479686214880095356}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6230', 'title': 'Canadian Shield', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Human population is sparse, and industrial development is minimal, while mining is prevalent.', 'Human population is sparse, and industrial development is minimal, while mining is prevalent.', 'The Canadian Shield, also called the Laurentian Plateau, or "" (French), is a large area of exposed Precambrian igneous and high-grade metamorphic rocks (geological shield) that forms the ancient geological core of the North American continent (the North American Craton or Laurentia). Composed of igneous rock resulting from its long volcanic history, the area is covered by a thin layer of soil. With a deep, common, joined bedrock region in eastern and central Canada, it stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada;']}}]}]