含粗粒金矿石化学样品采集实验研究

Experimental research on chemical sample collection of coarse-grained gold ores

含粗粒金矿石中的金分布极不均匀,样品代表性差,采样带来的误差远大于样品加工和分析环节产生的误差,导致不能准确评价矿石品级。实验选择陕西省安康北部金矿带中3个不同地区(汉阴长沟、汉阴金斗坡和石泉羊坪湾)金矿,采用10 cm×5 cm、10 cm×10 cm、20 cm×3 cm、20 cm×5 cm、20 cm×10 cm等5个不同采样规格采集样品,采用重砂法分析重砂和轻矿物中的金品位。结果表明:采样规格对同一采样点的金品位有明显的影响,但并未体现大规格取样代表性的优势,而小规格取样比大规格取样有更高的金品位;不同采样点对金品位的影响极为显著,特别是金斗坡金矿和羊坪湾金矿,采样位置的选择极为重要。为确保采样的代表性,采样规格以10 cm×5 cm为宜,采样量15～20 kg较为经济有效。

Because of the extremely uneven distribution of gold in the samples and bad representativeness of samples in the coarse-grained gold ores,which cause errors far greater than those from sample processing and analysis,it is impossible to accurately evaluate the grade of this kind of ore.In this paper,gold mine in 3 different areas (Changgou and Jindoupo from Hanyin,and Yangpingwan from Shiquan) of the coarse-grained gold ore belt in northern Ankang, Shaanxi Province,were selected. Samples were collected with 5 different sampling specifications,including 10 cm× 5 cm,10 cm×10 cm,20 cm×3 cm,20 cm×5 cm and 20 cm×10 cm.The gold grade in heavy and light minerals was analyzed with heavy fraction method.The results show that the sampling specification has obvious influence for the gold grade from the same sampling point,but large-scale sampling does not exhibit more representativeness.Meanwhile,small-scale sampling shows higher gold grade than large-scale ones;sampling points have significant influence on gold grade,especially in Jindoupo and Yangpingwan Gold Mine.The sampling spot choice is extremely important.To ensure the representativeness of sampling,the sampling specification is best to be 10 cm×5 cm and the sampling weight be 15-20 kg.