Acid mine drainage results from acidic water formed belowground that makes its way to the surface; the acidic water is formed as a result of the flooding of abandoned mines where the underground watera) reacts with a type of rock, pyrite, which releases iron and hydrogen ionsb) reacts with sulfur dioxide and nitrogen dioxide to form sulfuric and nitric acidsc) flushes out the chemicals used in the mining processd) permeates a limestone layer that lowers the pHe) reacts with copper and aluminum to form pyrite rock and hydrogen ions

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.