The concerns come two years after Glencore was granted approval to lift the rate of mining from 2.5 million tonnes of ore annually to 5 million tonnes and the yearly yield of zinc and lead bulk concentrate from 360,000 dry metric tonnes to 800,000 dry metric tonnes.
Refer to the input text as context and select the correct relationship between 'Glencore' and 'mining' from the available options.
Options: legal form, location of formation, industry, brand