Source Identification and Quantification of Seepage Water in a Coastal Mine, in China

Abstract

The Sanshandao gold mine, which is the largest coastal mine in China, is under threat from seawater intrusion and water inrush. The objective of this study is to determine the water end-members (seawater, freshwater, and brine) of the seepage water in the mine and quantify the proportion of end-members. Non-conservative ions and ion exchange were identified by using hydrogeochemical analysis. Then, the principal component analysis (PCA) was used to identify the end-members of mine water. Three end-members were identified, so a ternary mixture model was applied to compute the mixing ratios. The potential water flow channels and the prevailing supply patterns were inferred by combining the results of mixing ratios with the tectonic and engineering geological conditions. The results indicate that the proportion of seawater in mine water is about 57%, the freshwater is about 16% and the brine is about 27% for the entire mine area, the prevailing supply pattern of seawater was lateral recharge, the water samples which were located in −510 m sublevel or in the northeast of prospecting line 2260 had high proportions of seawater, the freshwater supplied the groundwater mainly through the secondary fractures developed area in a vertical recharge and the influence depth was about −500 m, and F3 was the largest tensile-shear fault in the study area and it was both a watercourse for seawater and fresh water.

Discrimination Methods of Mine Inrush Water Source

“…Conventional chemical analysis of water is a widely utilized method for discriminating water sources in groundwater and inrush incidents [10]. This method involves analyzing major ions and comprehensive water quality indicators to determine the water quality types of the aquifer and the inrush water.…”

“…The conventional hydrochemical method serves as the primary means of analyzing the primary ion content, which includes indicators such as Ca 2+ , K + , Na + , SO 4 2− , HCO − , Mg 2+ , Cl − , CO 3 2− , dissolved oxygen, alkalinity, acidity, pH value, and mineralization degree. This method plays a crucial role in determining the water quality classification of both the aquifer and the water influx [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Additionally, it proves effective in identifying a single water source characterized by significant differences in water quality attributes within the aquifer.…”

Analysis of Acoustic Emission Characteristics and Failure Mode of Deep Surrounding Rock of Sanshandao Gold Mine

“…The alteration zone has been obviously zoned through multi-stage tectonic movement, and it basically spreads along the tendency and strike of fault F1. The gold deposits mainly occur in the cataclastic rocks within 40 m of fault F1, and they mainly consist of veined and reticulated mineralized rocks [ 29 , 30 , 31 , 32 , 33 ].…”

Application of Clustering and Stepwise Discriminant Analysis Based on Hydrochemical Characteristics in Determining the Source of Mine Water Inrush

“…Its main idea is to construct a linear combination of raw variables and compress multiple groups of complex variables into simple comprehensive variables to achieve the effects of compressing data and extracting main information [20][21][22][23][24]. In order to avoid the influence of different data units on the calculation results, the raw data was standardized by z-scores firstly, n samples were x i = ðx i1 , x i2 , ⋯, x ip Þ, and the formula was as follows [25,26]: 4 Geofluids Z ij is the standardized data, and x j and s 2 j are the mean and variance of j column elements of the raw data, respectively.…”