Question: the most important mineral product of northern chile is
[{'answer': 'copper', 'provenance': [{'wikipedia_id': '5489', 'title': 'Chile', 'start_paragraph_id': 2, 'start_character': 85, 'end_paragraph_id': 2, 'end_character': 91, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5489', 'title': 'Chile', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 540, 'bleu_score': 0.9567517979328871, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6740607304494785555}, 'section': 'Section::::Abstract.'}]}]