一前言日本明延矿业所神子畑选矿厂的生产近况曾在“浮选”44号和“日本矿业会志”1046号的两篇文献中详细报道过。其中也介绍了近十年来该厂生产改进的情况。目前,该选矿厂所进行的一系列设备大型化的改进工作虽已告一段落,但由于人员材料、电力和运输费用等的增加,加之长期来铜价的下跌等,生产处于困难之中。为了改善这种情况,对占明延矿业所冶炼收入的50％的铜和25％的锌的浮选作业,并采取了措施,除进行了一些设备的加强外,对生产方针也重新加以 I. INTRODUCTION Recent developments in the production of the Shizuoka Concentrator at the Minyong Mining Group in Japan were covered in detail in two articles, “Flotation” No. 44 and “Japan Mining Association,” No. 1046. Which also introduced the past decade to improve the plant’s production situation. At present, a series of large-scale improvement work on equipment at the beneficiation plant has come to an end. However, due to the increase in staffing materials, electricity and transportation costs, coupled with the long-term decline in the price of copper, production is in difficulty. In order to ameliorate this situation, measures have been taken to flotation 50% of copper and 25% of zinc smelting the mine’s assets, and some measures have been taken to re-establish the production policy