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Riots On Monday , January 31 1966 , a group of miner s from Zwartberg went to the mines at Waterschei to rally their colleagues for a strike against the closing of the mine of Zwartberg .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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