Mineral exploration under deep cover: Improving the effectiveness of ZTEM surveys for porphyry copper exploration in the Canadian cordillera

深层矿产勘探：提高加拿大山脉斑岩铜矿勘探 ZTEM 勘察的有效性

• 批准号: 413264-2011
• 负责人: Richards, Jeremy
• 金额: $ 10.34万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Strategic Projects - Group
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=530765
• 关键词: Mineral; exploration; under; deep; cover

As the discoveryrate of new mineral deposits diminishes in mature exploration regions such as the Cordillera of western Canada, exploration is increasinglyfocusing on harder-to-find deposits that are either covered by younger geological formations, or form extensions of known deposits at depth.The most common tools used for this type of subsurface exploration are airborne geophysical methods, such as electromagnetic (EM) and magnetic surveys. Airborne EM has proven particularlyeffective in identifying ore-bodies consisting of metal-sulfide minerals, because of their high electrical conductivityrelative to many other common rocks and minerals. Combined with other methods such as aeromagnetic surveys, EM surveys have been successfullyused to locate mineralized zones within exposed ore-forming systems. However, where the target is deeplyburied or covered byyounger rock sequences, these geophysical signals cannot currentlybe uniquelyinterpreted, with the result that exploration companies must expend significant time and moneyto drill targets that commonlyprove to be barren.Inan attempt to provide more constraints on the interpretation of deep EM surveys, we propose to evaluate andimprove the effectiveness of one particular airborne EM method, ZTEM (Z-axis Tipper Electromagnetic survey), which is widelyused for deep (down to 2 km) mineral exploration and for exploration in covered terrains. ZTEM is a proprietarytechnique of Geotech Ltd. We will do this byusing a large ZTEM database made available to us byour industrypartners, which we will calibrate over known mineral deposits. We will then use these calibrations to test the abilityof the method to uniquelyidentifymineralized zones within partiallyexposed or partiallyexplored deposits. Finally, we will evaluate the method's potential to identifynewmineralization targets in completelyblind settings, for example beneath younger cover rocks.

随着在加拿大西部科迪勒拉等成熟勘探地区发现的新矿床越来越少，勘探越来越多地集中在难以发现的矿床上，这些矿床要么被较年轻的地质构造所覆盖，要么是已知矿床在深处的延伸。用于此类地下勘探的最常用工具是航空地球物理方法，例如电磁（EM）和磁测量。航空电磁已被证明在识别由金属硫化物矿物组成的矿体方面特别有效，因为它们相对于许多其他常见岩石和矿物具有高导电性。电磁测量与航磁测量等其他方法相结合，已成功地用于定位暴露的成矿系统中的矿化带。然而，当目标被深埋或被较年轻的岩石层覆盖时，这些地球物理信号目前还不能被唯一地解释，结果是勘探公司必须花费大量的时间和金钱来钻探通常被证明是贫瘠的目标。为了对深部电磁测量的解释提供更多的限制，我们建议评估和改进一种特定的机载电磁方法ZTEM （z轴倾斜器电磁测量）的有效性，该方法广泛用于深部（低至2公里）矿产勘探和覆盖地形勘探。ZTEM是Geotech有限公司的专有技术。我们将通过使用您的行业合作伙伴提供给我们的大型ZTEM数据库来做到这一点，我们将对已知的矿藏进行校准。然后，我们将使用这些校准来测试该方法在部分暴露或部分勘探的矿床中唯一识别矿化带的能力。最后，我们将评估该方法在完全盲环境下识别新矿化目标的潜力，例如在较年轻的覆盖岩层下。