10th Asian Regional Conference of IAEG (2015)

Hazard analysis for Jingerquan mine based on GPS monitoring technology

Ma Fengshan(1), Ding Kuo(1), Zhu Jianjun(2), Tian Maohua(2)(1) Key Laboratory of Shale Gas and Geoengineering, Institute of Geology andGeophysics, Chinese Academy of Sciences, Beijing 100029, China
E-mail: 309520428@qq.com(2) Hami Jingerquan Mining Co. Ltd., Hami 839000, China
Abstract
Analysis of mining hazard is a complex engineering problem. Taking Jingerquanmine for instance. it adopted the shallow-hole shrinkage method at the previous miningstage which severely disturbed the overlying rock mass. Therefore, the filling method isused instead in the later stage. Based on the result of GPS monitoring, the surface
deformation is analyzed and the deformation region is divided into three parts according torock mass deformation mechanism and cracks process. As the mining activity continues,
surface deformation region will expand. This article laid a theory basis for ensuring mining
safety.
Keywords: mining engineering, hazard analysis, GPS, surface deformation
shrinkage mining method in 2010. The filling method

1. Introduction

caneffectively

reducethesurroundingrock

Owing to the rapid development of nationalmovement and protect the surface integrity (Wangeconomy and the increasing demand for mineraland Gao, 2003). While because of the overlying rockresources, the mining scale of underground resourcesmass stability is low, the surface deformation is still

increases continuously. Due to the complexity ofin further development (Li and Lu, 2006; Sun andmining method, geological conditions, in situ stress

Jiang, 2008; He and Yan, 2000).

and geological structure (Huang and Chen, 2009;

In this paper, based on field survey results andFang and Peng, 2004; Wang, 2006; Xi and Chen,

monitoring2011), surface deformation and rock mass movement

characteristics of Jingerquan mine was analyzed andcaused by underground mining is a complicatedthe deformation region was divided into three parts

engineering problem.

according

Jingerquan copper-nickel mine was founded in

data,

to

the

thesurface

mechanismofdeformation

rockmass

deformation and the process of cracking, and the2002 and put into production in 2005, due to thehazard of the area was also studied.

limitations of materials and funds, shallow-holeshrinkage mining method was adapted in the early

2. Geological condition and mining situation

mining stage. Affected by violent mining procedures,the integrity of overlying rock mass integrity wasJingerquan mine is located in the south of thedestroyed, a large area collapsed and a wide range ofCentral Asian orogenic belt, Regional tectonic line

surface cracked (Deng and Li, 2001). As a result, thedirection is NNE, 32 faults are mapped, most of

filling method was chosen instead of shallow-holewhich are high angle reverse faults. Many fractures

110th Asian Regional Conference of IAEG (2015)

develop in the mining area, and the main fracture lies

Outside the area of ground subsidence, groundin the central part of the mining area. Its strike angle

surface deformation evolves into gradual type.

is NEE, dip direction is SSE and inclined to 80° -85°.
Constantly affected by late tectonic activity, foliated

3.2 Surface cracks

and mylonitic structures and other weak structural

A total of 12 surface cracks in mine and two crack

planes developed in the contact zone between the orezones constituted of the north crack zones and theand rock, There’s a large difference between thesouth crack zones are observed. The sedimentation

lithology of both side, the south side outcrops gabbro,

basin boundary divided by 20 mm a year is shown inmonzonitic granite and metamorphic rocks in

Figure 2.

carboniferous strata and the north side outcrops
gabbro, diorite, mirror spring basic - ultrabasic rock.
Jingerquan mine was put into production in 2005
and delimit the mining depth for 1362 m to 840 m
elevation. According to the distribution location
orebody can be divided into two parts (Fig.1).
Shallow-hole shrinkage mining method was used
amidst the 1090 m and 1047 m and 989 m middle
sections.

Since

groundpressurecontrolandmanagement is difficult in mining and the fissuresspread widely to the surface, as a result, the rockabove mined-out areas were turned into granularstructure. So the filling method was chosen instead ofshallow-hole shrinkage mining method in 2010
through 965 m and 925 m middle areas.

Fig. 2 Location of Surface cracks
The north crack zone mainly comprises tensile
cracks and exposed on the northern edge of thesurface subsidence basin. The development of thenorth crack zone is parallel to the edge of subsidencebasin. It is composed of seven fractures with goodextensibility. The total length is about 400 m. The
crack belt get a characteristic of intermittent

Fig. 1 Mining method

development and has a tendency to breakthrough.
The south of Surface subsidence basin edge has not

3. Monitoring data

yet found that the tensile fracture.
3.1 Ground subsidence
Ground subsidence can be seen since the fieldsurvey and ground surface monitoring for the firsttime in 2013, surface subsidence have been extended
to the outside along with the mining activities.

210th Asian Regional Conference of IAEG (2015)

3.3 Surface deformation
The mine was monitored for four times a year
from July 2013 to April 2015 with GPS monitoring
method, There are eight monitoring lines(No.94No.101) and 101 monitoring points in total. They
cover all the subsidence and deformation area in themine.
Displacement vector diagram and displacement
contour map is shown in Figure 5.
From the above monitoring results, the surface
deformation area is similar to an irregular round,Fig. 3 Tension cracks

there is only one subsidence center and the directionof regional deformation points to the subsidence

The south crack zone is shear cracks and exposed

center. Maximum vertical displacement is 629.09 mm,

inside the surface subsidence basin edge. It is

It shows that there is a strong deformation near thecomposed of six cracks. The crack zone get a

subsidence center. The vertical displacement ofcharacteristic of soil extrusion bulge and arch whichmonitoring points is shown in Table 1. The area

the height is about 5mm, Besides, X cracks exposed

whose vertical displacement is larger than 50 mm

near the subsidence center and arranged pinnate

accounts for 10.40% of the total mining area, locatedright-handed.

at the center of the mining subsidence within 70
meters. And vertical displacement is less than 10 mm
accounts for 72.69% of the total area, the subsidence
area is relatively concentrated and the rest of theregion as a whole remained stable.

Fig. 4 Shear cracks
Table 1 Percent of vertical displacement from July 2013 to April .2015
Vertical<[-10][-100]-[-50][-50]-[-30][-30]-[-10][-10]-[0][0]-[20]

displacement

mmmmmmmm

mmmmPercent

6.08％

4.32％

6.43％

10.48％

49.68％

23.01％

310th Asian Regional Conference of IAEG (2015)

Fig. 5 Contour of superficial vertical displacement
4. Analysis of surface hazard

4.1 fracture zone
There is no limit to the lateral stress around theCombining
deformation, thewith

themechanism

featureofof surfacerockvertical tubular damage area, therefore, the surface

mass

deformation and fractures will develop at a rapid

deformation and the process of cracks, the surface

speed until mining stop. The area is named fracture

deformation zone is divided into three areas: fracturezone.
The accumulative deformation of surface iszone, deformation zone and the stable zone (Fig.6).
We will describe the mechanism and deformation

originallystable,andthenenteredarapidcharacteristics of the three zones respectively.

deformation stage, the curve of the accumulation
deformation with time in the zone is polyline, slow
after the first steep, its representative points for F042
and F052.
The surface cracks in fracture zone is on a large
scale and the maximum crack have a width of 40 cm.
The cracks are in the stage of slow growth and havesmall hysteresis relative to the mining.

Fig. 6 Surface deformation area4

10th Asian Regional Conference of IAEG (2015)

Fig. 7 Horizontal displacement of F042

Fig. 9 Horizontal displacement of GM08

Fig. 8 Horizontal displacement of F052

Fig. 10 Horizontal displacement of 97-7

4.2 deformation zone

4.3 stable zone

With the increase of the distance of the verticalIn the whole deformation area, the stable zone has

tubular area, the lateral stress increase while justthe farthest distance to the vertical tubular area, thebending deformation occurs. This area is known aslateral stress is close to the original ground stress.

the deformation zone.

The region located at the outer edge of the ground

Accumulative deformation to the surface is given

surface caused by the mining, its cumulative

priority to with stable deformation and the curve ofdeformation is small and the error in the process isthe accumulation deformation with time in the zone isbigger than the accumulative deformation value, as alinear. Its representative points for GM08 and 97-7.

result, the curve of the accumulation deformation

The size of surface cracks in deformation zone iswith time in the zone is fluctuate. Its representativestill large but much smaller than that in fracture zone,

points for 94-9 and 95-4. There is no crack in thisthe width of cracks ranges between 0.5 ~ 3.0 cm. The

area.

cracks in the deformation zone have a more apparent
hysteresis relative to the mining than fracture zone.

Fig. 11 Horizontal displacement of 94-95

10th Asian Regional Conference of IAEG (2015)

Reference
DENG Jian, LI Xi-bing, GU De-sheng (2001):
Ground pressure and control techniques in
non-pillar continuous mining method [J]. The
Chinese Journal of Nonferrous Metal, Vol. 11, No.

4, pp. 666-670.
FANG Jian-qin, PENG Zhen-bin, YAN Rong-gui(2004): The law of tectonic stress mining groundFig. 12 Horizontal displacement of 95-4

surface subsidence and its engineering treatment
method [J]. Journal of Central South University ofTechnology (Natural Science), Vol. 35, No. 3, pp.

5. Result and discussion506-510.
Because of the considerable development ofHE Yue-guang, YAN Rong-gui, ZENG Zhuo-qiao

mining structure and broken rock mass, the stability(2000): Law of mining surface movement by theproblems of the engineering rock mass get serious.

effect ofAccording to the analysis of vector and displacement,

Metallurgical Engineering, Vol. 20, No. 3,filling method cannot completely avoid the surface of

pp.12-14.

tectonic stress[J].

Mining anda wide range of ground fissure. Since theLI Xiao, LU Shi-bao, LIAO Qiu-lin, DU Guo-dong

shallow-hole shrinkage mining method has greatly(2006): Distribution characteristics and field

weaken the integrity and stability of the overlying

monitoring of ground fissures caused by backfill

rock mass, a wide range of surface subsidence andmining [J]. Chinese Journal of Rock Mechanics

ground fissures still happened.

and Engineering, Vol.25, No. 7, pp.1361-1369.

In our research, the surface deformation caused

Sun Xiu-bo, Jiang Yong-zhen, Liu Mao-hua, Zhu

by underground mining is analyzed and further

Guang-shan (2008): Characteristics of grounddeformation mechanism of underground mining isfissures and the formation mechanism is analyzed

described, we divided the surface deformation zone

in FuShun, The Chinese Journal of Geologicalinto three areas: fracture zone, deformation zone andHazard and Control, Vol.19, No. 4 , pp.42-45.

the stable zone. As mining activities continues, theWang Jian(2006): Study on Ground Subsidence Law

surface deformation is still in development, so theirof East District in Chengchao Iron Mine anddevelopment trend and influence on the surface

Displacement Mechansim of Main East Shaft,structures need to be further investigated.

Metal Mine, Vol. 358, pp. 7-11.
WANG Zheng-hui, GAO Qian(2003): Study onmechanism and stability of filling in stoping

Acknowledgments

cemented fill method [J]. Metal Mine, Vol. 328,

No. 10 , pp. 18-20.

The study was sponsored by the National NaturalScience Foundation of China (Grant Nos. 41372323,

XI Ren-shuang, CHEN Cong-xin(2011): Study of41172271) and was a science and technology support

influence of discontinuities on rock movement

project of the Xinjiang production and construction

and surface deformation in eastern area ofcorps (Grant No. 2014AB034). Grateful appreciation

Chengchao iron mine [J]. Rock and Soilis expressed for this support.

Mechanics, Vol. 32, No.2, pp. 532-537.

6