上次我們佛子嶺工地搬運工人朱建民等改裝了沙石篩子;這個改裝的成功,把開採沙石的效率提高兩倍餘,節省國家財富二十一億元;這是一件動人的大事。但在這件事情中的另外一種相反的情况,是值得來提一提的。佛子嶺水庫工程所需的黃沙、石子,都是在工地附近開採的。最初開採的辦法是:用搖篩和淌篩兩種篩法。效率每工最高僅零點五无公方。這辦法太笨 Last time, we built a sandstone sieve at Zhujian Min, a porter at our Foziling site. The success of this conversion has raised the efficiency of extracting gravel more than twice and saved 2.10 billion yuan of national wealth. This is a moving event. But the other opposite in this matter is worth mentioning. Foziling reservoirs required sand, gravel, are mining in the vicinity of the site. The initial mining approach is: shake sieve and trickle sieve two sieve method. The maximum efficiency of each job is only 0.5%. This method is too stupid