William Nicholl marked out a 5 acres (20,000 m2) claim, calling it "Martha" after a family member. Several smaller claims were later merged to form the Martha Company. By 1882 the first battery to break gold-bearing rock was in operation. The Martha Mine eventually grew into one of the world's most important gold and silver mines, after industrial cyanide processes made recovering gold from the low-grade ores easier. Waihi prospered with the mine, by 1908 being the fastest-growing town in the Auckland Province, three times the size of Hamilton.
Some environmental protests occurred during the 1987 consenting process for further mine operations. In 2001, subsidence in the area caused a collapse of a house, and the operating company has recently agreed to pay compensation to about 130 households for various negative effects due to noise, blast vibrations and dust.