Simmer and Jack,  · Simmer and Jack Mines Ltd (until 1924 known as The Simmer & Jack Gold Mining Co. Ltd.) is a South African company which was founded in 1887 by the German August Simmer and Scotsman John Jack, shortly thereafter selling the majority shareholding to Gold Fields of South Africa Ltd. The company was listed until 2013 at the Johannesburg Stock Exchange.IsaMill,  · For comparison, the power intensity of a ball mill is about 20 kW/m 3. This high power intensity allows the IsaMill to produce fine particles at a high throughput rate. [8] The high power intensity of the IsaMill comes from its high stirring speed of about 20 meters per second ("m/s").Grinding Ball,  · Grinding Ball, ALLSTAR INDUSTRY GROUP LIMITED, a certified ISO 9001 company, is the world-leading manufacturer of grinding media ball, grinding steel ball, forged steel ball, casting steel ball with annual production capacity of 100,000 metric tons.