How does mining affect climate change?
Some impact, but generally not a huge amount at least on an individual site basis.
Also, cutting trees down to make way for mining operations does reduce the value trees having in absorbing CO2 put into the atmosphere. Some mining companies, for example in the oilsands of Alberta, Canada, do have an obligation to re-plant forests somewhere else to offset the trees they cut down. But, not too much can be done to reduce emissions from mining trucks and shovels, except to keep them in good operating conditions.
However, mining overall is a small contributor compared to coal-fired power plants and billions of cars, trucks, buses, trains and air planes in our society.