Download or read book Trends in Practice and Costs of Concentrating Copper Ores written by T. G. Chapman and published by . This book was released on 1934 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past 20 years the milling of copper ores as practiced in the larger concentrators has changed to such an extent that comparatively few of the machines in use at the beginning of this period remain in service today.