A mineralogical study of the Lin Ma Hang Pb-Zn deposit, NE Hong Kong

Abstract

Lin Ma Hang Mine is located at the border of the New Territories and mainland China. It was a closed area for the past decades and was opened to general public since 2012. Lin Ma Hang Mine has 6 levels in total, this project was focused on level 6 , as other levels are already collapsed or in very dangerous condition.

Literature review, rock examination and microscopic study are the three main tasks I have to do for the study. Literature review is mainly based on these two literatures: “Geology of the Lin Ma Hang Lead Mine, New Territories, Hong Kong” by Davis and Snelgrove, and “The geology of the Lin Ma Hang Lead Mine, New Territories, Hong Kong” from Newsletter Vol 9 No.4 of Geological Society of Hong Kong. Both literatures were focused on the geological settings, history and the structure of the mine. It also mentioned briefly the minerals in the mining site, it includes pyrite, galena, sphalerite and chalcopyrite. Main production of the mine were lead and zinc. Others minerals including copper, iron, and more interestingly, silver and gold were also reported.

After site visiting to Lin Ma Hang Mine for understanding the local geology of the mine, microscopic study had been performed by using the rock samples from professor Zhou Mei-Fu’s research team.

For the microscopic study, 26 thin sections were studied physically and chemically. Three equipment were involved in the study: optical microscope and Scanning Electronic Microscope (SEM) were used for physical analysis, to find out if there is any sequence of the mineral deposition. Electro-Microprobe (EPMA) was used for chemical analysis, to see if there is any other elements found in the minerals, such as gold and silver. The findings from the geological study and the microscopic study are going to be discussed and illustrated in this paper.