Imaging Karatungk Cu-Ni Mine in Xinjiang, Western China with a Passive Seismic Array

Peixiao Du,Liang Zhao,Jian Wang,Wenjiao Xiao,Yang Li,Jing Wu,Mark Douglas Lindsay,Huaiyu Yuan,Chunming Han

doi:10.3390/min10070601

Abstract

Karatungk Mine is the second-largest Cu-Ni sulfide mine in China. However, the detailed structure beneath the mine remains unclear. Using continuous waveforms recorded by a dense temporary seismic array, here we apply ambient noise tomography to study the shallow crustal structure of Karatungk Mine down to ~1.3 km depth. We obtain surface-wave dispersions at 0.1–1.5 s by calculating cross-correlation functions, which are inverted for 3D shear-wave structure at the top-most (0–1.3 km) crust by a joint inversion of group and phase dispersions. Our results show that low-velocity zones beneath Y1 ore-hosting intrusion (hereafter called Y1) at 0–0.5 km depth and northwest of the Y2 ore-hosting intrusion (hereafter called Y2) at 0–0.6 km depth are consistent with highly mineralized areas. A relatively high-velocity zone is connected with a weakly mineralized area located to the southeast of Y2 and Y3 (hereafter called Y3) ore-hosting intrusions. Two high-velocity zones, distributed at 0.7–1.3 km depth in the northernmost and southernmost parts of the study area respectively, are interpreted to be igneous rocks related to early magma intrusion. Furthermore, the low-velocity zone at 0.7–1.3 km depth in the middle of the study area may be related to: a possible channel related to initial magma transport; mine strata or a potentially mineralized area. This study demonstrates a new application of dense-array ambient noise tomography to a mining area that may guide future studies of mineralized regions.

Highlights

Karatungk Mine, located on the southern margin of the Altay Mountains, is the second-largestCu-Ni sulfide mine in China (Figure 1) [1,2,3]
We find that velocity heterogeneities spatially correlate well with the distribution of major ore-hosting intrusions and mineralization of ore-hosting intrusions
We propose that a combined approach with the Ambient noise tomography (ANT) and a dense array setup may be a potentially feasible tool to map Cu-Ni sulfide orebodies in mines

Summary

Introduction

Karatungk Mine, located on the southern margin of the Altay Mountains, is the second-largestCu-Ni sulfide mine in China (Figure 1) [1,2,3]. The surface area of the mine is ~13 km , and the reserves of the mine were re-predicted to be 1,240,000 tons in 2005 [4]. This mine still has a relatively large stable mining value. Northwest striking folds and thrusting faults are dominant structures in the mine (Figure 1b,c), and the intersection of folds and faults are favorable for intruding of ore-hosting intrusions [5,6]. There are three major ore-hosting intrusions named Y1, Y2, and Y3, respectively (Figure 1c).

Methods

Results

Discussion

Conclusion