Coal in Australia. Right now, coal is Australiaâs primary fuel source for generating electricity at around 73 percent. Black coal is found across Australia. Brown coal, sometimes called lignite, is a relatively soft material, which has a heating value of about one-quarter of black coal.
noun. The definition of abrasive is something that is harsh or rough, often to an unpleasant degree. An example of abrasive is the attitude of your boss who is always short tempered and yelling at you. Sand paper or SOS pads are examples of abrasives.
Abrasion is the grinding and wearing away of rock surfaces through mechanical means of other rock/sand particles. This process can be understood with how a piece of chalk works. As you scrape a piece of chalk against a board to draw/write, particles of the piece of chalk rub off to make a line on the board and the piece of chalk wears down and gradually becomes smaller.