AMT技术在黔中水田坝地区铝土矿勘查中的应用

Application of AMT technology in bauxite exploration in Shuitianba,Central Guizhou

贵州铝土矿露头及浅覆盖区勘查工作已近乎完成,目前铝土矿多为隐伏矿,本次黔中水田坝地区铝土矿勘查主要寻找中深部隐伏矿体。黔中水田坝地区铝土矿位于黔中铝土矿之南东,赋矿层位为石炭系九架炉组(C_1jj),其底板为寒武系娄山关组地层(∈_(2-3)ls),二者为假整合接触。铝土矿的品位、厚度严格受到不整合面上岩溶洼地、岩溶漏斗的影响,平面上变化较大。根据矿区含铝岩系与顶底板的物性差异,本次在黔中水田坝地区铝土矿的勘查中,选用音频大的电磁测深法(AMT)进行勘查,划分含铝岩系与顶底板的界线及含铝岩系厚度,结合地质测量及探矿工程资料综合分析,圈出含矿有利部位,进而钻探验证,取得了较好的效果。

The exploration of outcrop bauxite and shallowly covered bauxite in Guizhou has almost been comple- ted. What remains to be explored is mostly concealed bauxite. The main purpose of this exploration is to search for middle and deep concealed bauxite in Shuitianba, Central Guizhou. The bauxite in Shuitianba is located in the southeast of the bauxite in Central Guizhou. Its ore-bearing stratum is Carboniferous Jiujialu Formation （Cljj）, its floor is Cambrian Loushanguan formation （ e 2_31s） , and the relationship of the two strata is parallel unconformi- ty. The grade and the thickness of the bauxite are influenced by karst depressions and dolines, and vary great- ly. Considering the difference of physical property between the aluminous strata and the roof/floor, we used the audio magnetotelluric sounding （AMT） method to divide the boundaries between the aluminous strata and the roof/ floor, and to determine the thickness of the aluminous strata. Combined with geological survey and comprehensive analysis of exploration data, we determined the favorable ore-bearing parts and verified it by drilling tests, achieving satisfactory results.