Drilling and blasting has been used since ancient times for mining and construction projects. Workers originally used hammering and chiseling which was very labor intensive. The discovery of explosive black powder in ancient India and China helped alleviate this drudgery. Black powder was initially used for signaling but later adopted for military use. It was first applied to mining in the 15th century. Liquid nitroglycerin was discovered in 1846 but was very hazardous. Alfred Nobel stabilized it by absorbing it into an absorbent material to create the safer dynamite explosive in 1876, revolutionizing the industry.