Alloy are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a "substitutional alloy". Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms respectively. In the case of the interstitial mechanism, one atom is usually much smaller than the other and can not successfully substitute for the other type of atom in the crystals of the base metal. Instead, the smaller atoms become trapped in the
Sundown Tin and Copper Mine and were mined from different shafts. With rising prices the mine was operating again in 1897, and much development work was carried out in 1898. By 1899 a smelter must have been erected, as 470 tons of ore was smelted for 53 tons of matte containing 30% copper and 50oz silver per ton, and 20 men were employed. More ore was raised in 1900, but the mine was under exemption through 1901-1903, a time of low copper prices. In 1904 the mine was described as having an open-cut on the tin portion, and on the copper section a tramway ran