potential of white marble resouces in luc yen district...

Mineral Exploration & Mining Technology 11

1. STUDIED AREA LOCATION The studied area is located in Luc Yen district, Yen Bai province (northwest of Vietnam), of about 100 km northeast of Yen Bai city by national road No. 70 and 2C, and 200 km northwest of Hanoi Capital by No. 3 national road (Fig 1. Studied area location map).

Fig 1. Studied area location map

2. REGIONAL GEOLOGY AND MINERALS The previous results by Vietnamese Geo-Division and foreigner Scientists showed that the area belongs to metamorphic limestone range, extended by NW-SE direction, and formed marble rocks. This limestone range has been considered since 1965 by regional geological research at 1:500,000 and 1:200,000 scale; mineral investigation and prospecting works at 1:50,000 and 1:10,000 scale; and particularly many limestone exploration projects have been carried out recently. According to the geological and mineral survey results at 1: 50,000 scale of group of sheets Yen Chau (Nguyen Van The, 2000) and the revised results of geological and mineral resources map at 1: 200,000 scale of Yen Bai, sheet F-48-XXI (Nguyen Vinh, 2004) and Bac Quang, sheet F-48-XV (Tran Xuyen, 2000), the geological structure is not complicated. Mainly the metamorphic rocks of Thac Ba formation and covered by the

ABSTRACT White marble resource (known as white limestone) in Vietnam in general and in Luc Yen district, Yen Bai province in particular is one of the strategic minerals in Vietnam. Since 1999, the white marble in Luc Yen has been interested by researchers and investors because of its value in use and highly economic efficiency, especially in the field of block , slab marble construction production, calcium carbonate powder and high-end jewelry. White limestone range in Luc Yen belong to An Phu (NP - ε1 ap) formation that consists of altered limestone, siliceous limestone, its thickness is about 450-500m, 12-14 km width, nearly 20 km length in NW - SE. The marble mineral are mostly in white marble, white gray, white gray color. Mineral components mainly are calcite from 97% to 100%. Until now, many mining and processing investors in Luc Yen has been successful applied appropriate scientific, technologies to put white marble products not only meet the domestic market but also to reach the market international.

NGUYEN Thi Thuc Anh PhD. In Geology,

Head of Department of Mineral Resources Management Faculty of Geology, Hanoi University of Natural Resources and Environment,

Vice Chairwoman of Luc Yen White Marble Association.

PPaappeerr IIDD 7766

Potential of White Marble Resouces in Luc Yen District, Yen Bai Province of Vietnam and Orientation For Development


marble limestone rocks named An Phu formation (NP - ε1 ap), and the followings are consists of the sericite - quartz schist, thin limestone layers, and shale of Mia Le formation, a little of unconsolidated Quaternary materials in the valleys and along the streams. The intrusions consist of syenite, granosyenite of Phia Ma complex and granite, granodiorite of Phia Bioc complex [4], [5]. The exploration results recently showed that Yen Bai province is one of the great potential regions of white marble of Vietnam. The distribution of white marble in Yen Bai is concentrated in three main areas, such as the 1. Tan Linh - An Phu, 2. Vinh Lac located in Luc Yen district (Fig 2. Geological map of Luc Yen area), and 3. Mong Son located in Yen Binh district, in which Luc Yen area is considered as a good potential in scale and quality to meet the high – end building and industrial minerals. Geological structure of white marble formation in Yen Bai is single incline that formed by thick layers of dolomite and calcite marble, with medium to coarse crystals, and disseminated sulfide minerals in some places. The rocks are exposed well but the quality is quite different in marble layers. They create a picture of mountainous ranges along the northwest-southeast direction. Strike and dip of marble layer is about 40-600 700 and developed along the left side of the Chay river, north of Thac Ba lake and extends from Khai Trung commune, through Tan Linh, Yen Thang, Lieu Do, Tan Lap, Minh Tien, An Phu, Phan Thanh, Vinh Lac of Luc Yen district to Xuan Long, Ninh Phuc, Mong Son commune of Yen Binh district.

Limestone of An Phu Formation (NP - ε1 ap), is composed of marble, altered limestone, striped marble, silica marble, thickness of 450-500m. Its distribution is about of 2-14 km width, nearly 20 km length in NW – SE direction (Fig 2. Geological map of Luc Yen area).

Fig 2. Geological map of Luc Yen area Quality of limestone of An Phu formation meets the requirements of block stones for paving and calcium carbonate powder for mineral raw materials of industrial applications. However, due to the major fault systems in NW - SE and the secondary system faults in NE - SW or in sub-meridional direction, the scheme of the region structure was complicated and directly impact on the quality of paving stones in the region. Along these fault systems, stones were strong crushed, cracked and can not use the whole products for paving. In Yen Bai province, the marble resources can be used for construction material is about 3.9 billion m3, and the reserves of 26 exploration projects up to June 2012 in area are 110.044 million m3 of block stone and 188.992 million tons of calcite carbonate powder (Fig 3,4) [1], [2].


Fig 3. White marble in Vĩnh Lạc (Luc Yen district)

3. QUALITY OF LUC YEN WHITE LIMESTONE AND USAGE The white limestone ore bodies in Luc Yen area distributed in upper subformation of An Phu formations, generally carbonate constitution has a relatively high natural white, thick layers or massive form. White and grey white limestone interbedded with gray-white and light pink marble layers Mineral components, mainly calcite (97% to 100%), graphite (less common, up to 2%), phlogopite (less common, up to 2%). Some places can find forsterite (to 20%).

Basic chemical compositions are as follows: CaO 45.55% to 55.01%, in average 53.91%; MgO 0.18% to 7.14%, in average 0.65%; T.Fe 0.000% to 0.079%, in average 0.025%; SiO2 0.21% to 2.85%, in average 0.68%, Al2O3: 0.000-0.015%, in average 0.008%; Mechanical and physical properties: brightness of 77.50% to 96.30%, average 92.00%, the density in average is 2.7 g/cm3; saturated compression resistance strength ≥ 500 kg/cm2; saturated tensile intensity ≥ 39 kg/cm2; soften coefficient ≥ 0.7%; bright coefficient ≥ 90%, pH average 9.4, particle size on 325 mesh screen from 0.05 to 4 %, particle size average 3.7 m.

The white limestone in Luc Yen meets the high qualitative requirements for building materials to decorative paving stones with block size ≥ 0.4 m3 and crushing

powder for industrial raw materials of various fields [2], [3].

Fig 4.White marble products in Luc Yen

4. THE STATUS OF MINING AND PROCESSING

4.1. Status in Yen Bai province The statistics on the number of mineral licenses in the provinces showed that Luc Yen in particular and Yen Bai province in general is one of region having a lot of enterprises invested in the field of white marble. According to the statistics of the Department of Trade and Industry of Yen Bai province (2012), up to June 30th 2012, Yen Bai province whole 28 mining licenses on white limestone in which 14 licenses are mining, 01 licenses is quiet; 09 licenses are building basically mine, 04 licenses were not operating. The exploiting activities are open-pit in medium and large scale by semi mechanization methods (scoop, loading, shipping, drilling and blasting). Especially in mines quarry, to get block the technique used diamond wired cutting machines. The total capacity of the mining licenses is 2.0 million m3 block stone; 13.25 million tons


crushed powder/year (6.91 million m3/year). Total of mining output of licenses during 2010, 2011 and 6 months of 2012 were 40,787 m3 of tiled stone; 5.42 million tons of crushed stone powder. Thus, compare to the mining licenses, mining capacity in fact was only 1% of block stones and 16% of stone powder. Total of investment capital is over 1,026 billion (about 51 million USD) and use a workforce of 1,290 people. In the current developing progress, the application of mechanization in mining and processing is indispensable requirement. However, some companies had not invested on infrastructure and technology, so the value and output were limited.

4.2. Mining and processing Status in Luc Yen district In Luc Yen district there are 22 mining licenses in which 7 licenses are in mining and processing to create products of block, produce slabs, and chips for grinding powder for industrial minerals and construction materials; and the remaining permits are ongoing the basic construction of the mine and have still not come into operation. The consumer market is mainly exported to China, India, Malaysia and other countries, a small portion supplied for cement production, carving stone and work of art.

Facing the competition increasingly with the leading contries in the white marble market such as India, Italy, the Middle East, Taiwan, China..., the enterprises in Luc Yen had flexibilities in applying the advanced technics and technology by importing equipments, investing up to trillions VND, using hundreds of local labor and contributed tens of billion VND to the local budgets. Exploiting technology had innovations more and more such as cutting layers from top to down, using diamond wire cutting machine (Fig.5,6,7). The mining and processing activities always request the aim for safety, security and protect for mineral resources. The main

products after processing are: block, slab, tile, chip stone, powder materials and most of percent have been exported to many countries in around the world.

Fig 5. Chain Gang saw devices at Tuong Phu mine

(Van Khoa Investment JSC)

Fig 6. Diamond wire Cutting machine and drilling

in Tuong Phu (Van Khoa Investment JSC)

Fig.7. Products of white marble blocks

of R.K Marble Co.Ltd. In addition to mining and processing of enterprises, now in Luc Yen district, there are about 17 households participating in crafting from marble around in the Hamlet 2 (Tan Linh Commune, Yen The town) and the junction of Khanh Hoa commune. In recent years, the demand for Luc Yen white marble crafting products are become increasingly. By the advantage of white marble resources together with gemstones, many work of art, artistic masterpieces of households in Luc Yen district crafted with various designs that bring high economic efficiency, creating a potential market in Yen The town and Khanh Hoa commune, attracted a lot of local and foreign tourists to


visit and purchase goods. The development of marble craft have contributed to promote Luc Yen district became a shopping center on stone products, handicrafts and tourism.

Production of mining and processing in Luc Yen

Year Block (m3) Slab (m2)

Chip stone for power

(m3) 2011 10,500 192,000 120,000

2012 20,000 200,000 50,000

During last years, mining and processing activities in Luc Yen were adversely affected by the financial difficulties happening all over the world that caused white stone market worldwide going down. Also, the price of raw materials and input devices was increased, tax policy was adjusted unstably, mechanism of tax calculation basing on the added value of block and processed production was really unreasonable, the recovery rate from block production was low. Facing these, enterprises in Luc Yen are finding reasonably solutions to save the resources.

Fig 8. The white marble processing factory of

Investment Corporation of Van Khoa Investment JSC

Fig 9. Cycling wastewater treatment station of

R.K Marble Co.Ltd.

Fig 10. Small slab factory in Luc Yen district, Yen

Bai provinceof R.K Marble Co.Ltd.

Fig 11.Factory in India of R.K Marble Co.Ltd.

5. ORIENTATION FOR DEVELOPMENT

1. Establishment of White Marble Association in Luc Yen Facing the mining and processing status on white marble, the enterprises in Luc Yen and local authorities in Yen Bai province had recognized the difficulties and challenges, and would like to cooperate in the investing activities to enhance the competition in the local and international market. In this situation, White Marble Association of Luc Yen was established on July 30th 2012. White Marble Association of Luc Yen is a organization of enterprises, businessman, householders that doing business together on marble trading in Luc Yen district. Main objectives of White Marble Association in Luc Yen:

- Protecting the rights and legitimate interests of its members;

- Cooperating in mining and processing technology and technics;


- Support for membership in information relating to market, law and connecting members with the State management agencies and local communities.

Although the White Marble Association has just established and organized the first meeting on November 29th 2012, there were many significant activities to members such as cooperation and exchange information related to business operations, market and share management experiences, expanding the cooperation with other professional associations to strengthen the Board of Association, promote prestige of organization and responsibilities for community and sustainable development of mining and processing industry of Vietnam and international integration (Fig.8,9,10,11).

2. Orienting the development in the future In the next stage, first in 2013, the Executive Committee agreed to approve activities and regulations for orienting the development: - The members will expand cooperation, exchange in the Association and others for investors, enterprises and groups that have the financial capacity and advanced technology to open the market, improve the mining and processing technology, protect and develop the white marble mining and processing industry of Vietnam and mining processing in Vietnam in general and in Luc Yen district in particular. - Participating in international scientific meetings to introduce the advantages of white marble resources of Vietnam, the scientific and technical progress and technology has been applied, raising the opportunities for investor as well as approaching success in the world of mining and processing on white marble sector. - Cooperation to set up processing plants to maximize using and recovery of resources and also give conditions opportunities for enterprises that are unqualified to open a

factory independently still have reasonable services to produce products that meet the market. - Through Luc Yen White Marble Association, other Associations, and prestigious institutions to develop and train human-sources in technics and management for white marble industry in Vietnam.

ACKNOWLEDGEMENTS The authors sincerely thank the Luc Yen White Marble Association, Department for Control of mineral operations (General Department of Geology and Minerals of Vietnam) for supporting information of the article.

REFERENCES [1]. Department of Geology and Minerals of Vietnam. Report on the mineral resources of Yen Bai province. Hanoi, 2005. [2]. General Department of Geology and Minerals of Vietnam. Collection of conference reports. Status on exploration, mining, extraction, processing and use of white marble in Vietnam and orientation of using. Hanoi, 2012. [3]. Phuong Nguyen et al. Report on results of White marble exploration in Lieu Do 4, Lieu Do Commune, Luc Yen District, Yen Bai Province. Geological archives. Hanoi, 2010.

[4]. The Tran Van et al. Report on results of geological mapping and mineral prospecting group of sheets Luc Yen Chau at 1:50,000 scale. Geological archives. Hanoi, 2000.

[5]. Vinh Nguyen et al. Geological mapping and mineral resources of Yen Bai sheet F-48 - XXI at scale 1:200,000. Geological archives. Hanoi, 2004.

[6]. Xuyen Tran et al. Geological mapping and mineral resources of Bac Quang sheet F-48-XV at scale 1:200,000. Geological archives. Hanoi, 2000.

potential of white marble resouces in luc yen district...

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