Final answer:
The biased sentence is "The process of following regulations may cost the company money in terms of productivity, but the cost is always worth it," as it expresses a judgement that seems to inherently value regulations without considering opposing perspectives.
Step-by-step explanation:
The sentence that illustrates the author's bias in the newspaper editorial is "The process of following regulations may cost the company money in terms of productivity, but the cost is always worth it." This statement shows bias because it asserts the value of following regulations without considering the coal companies' perspective or the actual cost-benefit analysis. It implies a judgement that the author believes the environmental protections and safety measures are intrinsically worthy, regardless of the economic impact on the companies.
The rest of the editorial appears to provide more neutral information about the coal companies' and miners' viewpoints and the environmental and health impacts of mining practices.