Critical Reasoning (CR) | That the application of new technology can increase the

That the application of new technology can increase the productivity of existing coal mines is demonstrated by the case of Tribnia's coal industry. Coal output per miner in Tribnia is double what it was five years ago, even though no new mines have opened.

Which of the following can be properly concluded from the statement about coal output per miner in the passage?

Boil it down - the average coal output per miner, for ALL of tribinia, has doubled over the last 5 years.
that's it.
this means
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