美国金属勘查发现和成功比率及定量评价模型

THE DISCOVERY AND SUCCESS RATIO OF EXPLORATION FOR USA METALS AND ITS QUANTITATIVE APPRAISAL MODELS

本文根据1940～1984年期间美国金属勘查的资料对其勘查活动特点(投资水平、勘查方向、主要发现、成功比率等)进行了初步研究并建立了定量评价模型以模拟其勘查成功比率及累积发现比率与时间系列和勘查投资的关系。研究结果表明,美国金属勘查投资具总体递增和局部波动特点;主要发现价值具周期性波动规律,波峰间隔平均为5～6年;主要发现滞后投资峰值时间一般为1～2年;反映了美国金属勘查的周期性和快速性特点。作者用幂函数很好地拟合了美国金属勘查的成功比率和累积发现比率,两者差别在于前者为递减幂函数模型,参数-1<B<0,后者为递增幂函数模型,参数0<B<1。文章对美国勘查活动的这些特点及影响因素进行了分析,并期望根据其定量评价模型对未来的勘查成功水平的趋势及波动进行预测。本文的目的还在于为我国的勘查活动提供参考和对比,以便进一步总结我国的勘查活动规律及定量评价模型。

Based on the historical data of exploration for USA metals, this paper has studied the explorative characteristics of USA metals (including explorative directions, cost level, main discoveries and success ratio, etc.) and presented the quantitative appraisal models for explorative success ratio and cumulative discovery ratio. The result shows that the expenditure and main discovery of USA metals are characterized by an increasing trend as a whole and some fluctuations in part. The mean interval of wave peak is 5～6 years. The main discoveries lag princi- ple investments for about 1～2years. Power function can be very good at simulating the explorative success ratio and cumulative dicovery ratio. The difference is that the former is a decreasing power function in which the para- meter -1<B<0, while the later is an increasing power function in which the parameter 0<B<1. Author thinks that the success level of exploration and possible fluctuations in the future might be predicted according to the characteri- stics of explorative activity of USA metals and the quantitative appraisal models. This paper also contributes to the exploration of China as a reference and a comparison. Many thanks should be given to Prof. G. C. Grender for his help with my collecting data of USA exploration.