成矿后构造破坏对矿床勘查类型的影响及勘查类型系数优化

现行勘查规范中,主要依据五个地质因素划分勘查类型,其中构造复杂程度因素对划分勘查类型的影响权重约10%。通过对多个矿床勘查类型的分析以及勘查工作经验的总结,研究构造复杂程度对矿床勘查类型的影响,发现成矿后构造破坏程度对矿床勘查类型划分的影响可能被低估。本文以湘潭锰矿为例,该矿床具有成矿后构造复杂、对矿体的破坏大等特点,勘探时将其划分为第Ⅱ勘查类型,以相应的勘查工程网度进行勘查,未能有效控制矿体;如果充分认识成矿后构造复杂、对矿体破坏大的实际情况,提高构造破坏程度对矿床勘探类型划分的影响权重,湘潭锰矿就会被确定为第Ⅲ勘查类型,方可有效控制矿体,也更符合地质实际。本文尝试将构造复杂程度对划分勘查类型的影响权重增大至25%,其勘查类型系数由0.1~0.3调整为0.1~0.9,即第I、第Ⅱ、第Ⅲ勘查类型的五个地质因素类型系数之和分别由2.5~3.0、1.8~2.4、1.0~1.7调整为3.0~3.6、2.2~2.9、1.0~2。在更充分认识成矿后构造破坏程度对勘查类型的影响后,可进一步优化矿床勘查类型系数,更合理地确定矿床勘查类型,进而改进对矿床的控制程度和勘查程度的评价。

Analysis of the influence of structural complexity on the exploration type and optimization of the exploration type coefficient

The current exploration code is based on five geological factors to classify exploration,in which the influence weight of structural complexity is about 10%. Through analysis of multiple types of mineral deposits and exploration experience summary, this work has studied the influence of structural complexity on the type deposit exploration, and found that the influence degree of structural destruction on the classification of ore deposits may be under-estimated. This paper presents a case study of the Xiangtan manganese mine on this subject, which is featured by complicated structure after mineralization and intense destruction of ore bodies. During the exploration, this deposit was classified into type II, and surveyed at a corresponding grid of the project, failing to control ore bodies effectively. If the post-mineralization structural complexity and the actual situation of the ore-body destruction had been fully recognized in advance, then their weights in classification of the survey type should be raised and the mine should be viewed as type III, which are more consistent with the real geological conditions and favorable for effective controlling of ore bodies. As an attempt, this work raised the weight for the mine to 25%, and the exploration type coefficient is changed from 0. 1~0. 3 to 0. 1~0. 9, namely the sums of coefficients of five geological factors for survey types I, II, and III are changed from 2. 5~3. 0, 1. 8~2. 4, 1. 0~1. 7, 2. 2~2. 9, 1. 0~2. 1 into to 3. 0~3. 6, 2. 2~2. 9, 1. 0~2. 1, respec-tively. By such changes, the effect of structural complexity on the exploration type has been adequately considered, which permits to further optimize the type coefficients of mineral deposits, reasonably determine the types of exploration, and better evaluate the degrees of control and prospecting to the mine.