Bell metal metal used is a high-tin alloy of copper and tin with approximately a 4:1 ratio of copper to tin (78% copper, 22% tin). This is a much higher tin component than that used in statuary bronze. A range of percentages of tin content can vary from 20 to 26%, depending on the founder who has arrived empirically at their own alloy ratio. It has been found that increasing the tin content increases the decay time of the bell strike, thus making the bell more sonorous. Taking into consideration overall properties, such as tensile strength, hardness, wear resistance, cast quality, sound,
Sundown Tin and Copper Mine 28 July 2000 having satisfied the following criteria. The place is important in demonstrating the evolution or pattern of Queensland's history. The Sundown Mine is of historical importance because of its combination of tin, copper and arsenic production, the primary product at any given time varying with the prevailing market condition. Thus at one site is a microcosm of the forces influencing the pattern of most mining in this region of southern Queensland. The Sundown Mine together with the Beecroft Mine and the Jibbenbar State Arsenic Works, is associated with the prickly pear eradication program. The place demonstrates rare, uncommon