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Methods for Digitizing Mine Plans and Data of Mined Out Areas

Vivika Väizene, Ingo Valgma Tallinn University of Technology (Estonia)

vivika.vaizene@ttu.ee, ingo.valgma@ttu.ee

Abstract— Oil shale and phosphate rock has been mined in

large area in Estonia. Questions about ground stability for long term, exact location of underground workings or geotechnical properties of mined out areas have been raised. Older mining plans since 1916 contain information which can be digitized with GIS mining software. It requires applying different mining engineering and geoinformation methods. Current study solves some of the spatial information related questions.

I. INTRODUCTION

Oil shale has been main source for power industry in Estonia. Phosphate rock and oil shale have been mined in large area due to the small height of the seam. Oil shale is located in eastern part of Estonia while phosphate rock basin is located in the North. Currently three oil shale surfaces mines and two underground mines are operating. All phosphate mines have been abandoned (Fig. 1.). Fourteen underground mines have been closed in the past. More than 1 billion tonnes of oil shale has been mined out on 460 km2 area since 1916, Fig. 2, Table II.

There are many questions about mined out areas which do not have solutions concerning ground stability [2] for long term, exact location of underground workings and pillars or geotechnical properties of mined out areas [12].

Fig. 1. Underground phosphate rock mining area in Maardu.

Fig. 2. Mined out oil shale mining area in North-East Estonia, from year 1916 to 2014.

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TABLE I

OIL SHALE UNDERGROUND AND SURFACE MINES

No. on the Map, Fig. 2. Mine in Estonian Mine in English

2 Kaevandus nr 2 Mine No.2

3 Kaevandus nr 3 Mine No.3

4 Kaevandus nr 4 Mine No.4

5 Kaevandus nr5 Mine No.5

6 Kaevandus nr 6 Mine No.6

7 Kaevandus nr 7 Mine No.7

8 Kaevandus nr8 Mine No.8

9 Kaevandus nr 9 Mine No.9

10 Kaevandus nr 10 Mine No.10

12 Kiviőli kaevandus Kiviõli mine

3 Käva 1 kaevandus Käva 1 mine

3 Käva 2 kaevandus Käva 2 mine

1 Kukruse kaevandus Kukruse mine

6 Sompa kaevandus Sompa mine

8 Tammiku kaevandus Tammiku mine

7 Viru kaevandus Viru mine

10 Ahtme kaevandus Ahtme mine

9 Estonia kaevandus Estonia mine

11 Viivikonna kaevandus Viivikonna mine

5 Kohtla kaevandus Kohtla mine

19 Küttejőu karjäär Küttejőu surface mine

13 Ubja kaevandus Ubja mine

14 Ojamaa kaevandus Ojamaa mine

15 Vanamőisa karjäär Vanamőisa surface mine

18 Aidu karjäär Aidu surface mine

16 Kohtla karjäär Kohtla surface mine

23 Sirgala karjäär Sirgala surface mine

21 Narva karjäär Narva surface mine

20 Viivikonna karjäär Viivikonna surface mine

17 Ubja karjäär Ubja surface mine

25 Pőhja-Kiviőli karjäär Pőhja-Kiviőli surface mine

22 Vanaküla karjäär Vanaküla surface mine

II. METHODS

One solution to get earlier information that could be usable nowadays is to digitize older plans with GIS mining software solving methods of mining engineering technologies and geoinformation.

First of all mine plans on paper have to be photographed or scanned with high definition equipment. Files have to be classified by mines, scales or coordinate systems. Oil shale mines have had different names during times, so it is important to determine which period exact name was used and how have the mining boundaries been changed. Mine plans scale varies from 1 : 1000, 1 : 2000, 1: 5000 to 1:10000. Mine plans scaled 1 : 1000 contain more detailed information about rooms and pillars, seam height, timetable, geological irregularities and technological data. Few shaft area plans are even scaled 1 : 500. Mining plans have been secret and coordinates were hidden or calculated with different methodology during Soviet regime (period from 1940 to 1991). Some plans have more than one coordinate system axis which are intersecting.

After the digital files are compiled, photos or raster images must be geo-coordinated. The main problem which causes inaccuracy is the fact that paper plans are stretched, degraded, torn up or soak through. For dealing with this problem, digitizing software offers several options that simulate manual repairing like: Affine Polynomial, 1st Order Polynomial, Thin Plate Spline, Natural Cubic Spline, Marcov Spline, Exponential Spline, Rational Quadratic Spline, Inverse Distance Squared, 2nd Order Polynomial and 3rd Order Polynomial.

Common transformation is Affine Polynomial, where axis orthogonality may change, but parallel lines remain parallel. When transforming files, sufficient amount of image registration points must be picked to ensure best result. While transforming areas by stretching attention must be paid to avoid stretching areas which already frost correctly. Once the file is geo-coordinated, it can be vectorized.

Fig. 3. Viivikonna surface oil shale mine.

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Fig. 4. Mechanized room and pillar mining in Viru oil shale mine.

Fig. 5. Hand mined area with backfilling in Kohtla oil shale mine.

Stability of underground mined areas and building conditions (Table II) on these type of land depend on the extraction time, technology [9] (Fig. 3., Fig. 4., Fig. 5., Fig. 6., Fig. 7.) and the thickness of overburden [6]. Influence to the environment could also be assessed [14].

Fig. 6. Mechanised long wall mining in Kohtla oil shale mine.

Fig. 7. Different mining technologies close to each other in small area.

TABLE II

LIMITATIONS FOR BUILDING AND LAND USAGE DEPENDING ON THE TYPE OF

UNDERMINED LAND [7]

Type of land Buildings, roads, etc Agricultural and forest land Steady No limitations Stable Only light buildings No limitation Subsided Considering the

possibility of size and nature of land deformations in the future

Considering possible changes of humidity regime, especially unfavourable composition of Quaternary sediments

Quasistable Generally building is forbidden, permission only for the project which has passed geotechnical expertise

Considering the risk of cultivated plant destroying, especially unfavourable composition of Quaternary sediments

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III. RESULTS

As a result spatial models can be made for fine calculations of stability areas, geotechnical properties or water movement (Fig. 8.) [1].

Fig. 8. Vectorized mine plan.

DISCUSSION

The situation with mining plans is similar to the rest of the world. State or private owners have had different attitude during previous times to the archiving resulting in loss of data [6][13][5]. For landscape, construction and environment the missing data causes large number of unpleasant surprises [3][4][8]. Water, underground space, spatial distribution of backfilling and resource calculations could be supported be digital spatial models [11][10]. Current study solves some of the spatial information related questions.

ACKNOWLEDGMENT

The paper is part of the study AR12007 Sustainable and environmentally acceptable Oil shale mining No. 3.2.0501.11-0025 mi.ttu.ee/etp and the project B36 Extraction and processing of rock with selective methods - mi.ttu.ee/separation, KIK14033 Stability of undermined areas in oil shale deposit, ETF 9018 Mine collapses in NE Estonia

– detection, identification and causes and Estonian Archimedes Foundation (project „Doctoral School of Energy and Geotechnology II“).

REFERENCES

[1] Karu, V. (2010). Spatial modelling tools in mining areas for improving mining process. Lahtmets, R. (Toim.). 8th International Symposium "Topical problems in the field of electrical and power engineering. Doctoral school of energy and geotechnology". II : Pärnu, Estonia, 11.01.-16.01.2010 (129 - 133). Tallinn: Elektriajam

[2] Karu, V. (2010). Stability problems in undermined areas. Lahtmets, R. (Toim.). 8th International Symposium "Topical problems in the field of electrical and power engineering. Doctoral school of energy and geotechnology". II : Pärnu, Estonia, 11.01.-16.01.2010 (134 - 137). Tallinn: Elektriajam

[3] Karu, V.; Valgma, I.; Kolats, M. (2013). Mine water as a potential source of energy from underground mined areas in Estonian oil shale deposit. Oil Shale, 30(2S), 336 - 362.

[4] Karu, V.; Västrik, A.; Anepaio, A.; Väizene, V.; Adamson, A.; Valgma, I. (2008). Future of oil shale mining technology in Estonia. Oil Shale, 25(2S), 125 - 134.

[5] Karu, V.; Västrik, A.; Valgma, I. (2008). Application of modelling tools in Estonian oil shale mining area. Oil Shale, 25(2S), 134 - 144.

[6] Orru, M.; Väizene, V.; Pastarus, J.-R.; Sõstra, Y.; Valgma, I. (2013). Possibilities of oil shale mining under the Selisoo mire of the Estonia oil shale deposit. Environmental Earth Sciences, 1 - 11.

[7] Reinsalu, E.; Valgma, I (2003). Geotechnical processes in closed oil shale mines. Oil Shale, 20(3), 398 - 403.

[8] Reinsalu, E.; Valgma, I.; Lind, H.; Sokman, K. (2006). Technogenic water in closed oil shale mines . Oil Shale, 23(1), 15 - 28. Reinsalu, E.; Valgma, I (2003). Geotechnical processes in closed oil shale mines. Oil Shale, 20(3), 398 - 403.

[9] Väizene, V.; Valgma, I.; Iskül, R.; Kolats, M.; Nurme, M.; Karu, V. (2013). High selective oil shale mining. Oil Shale, 30(2S), 305 - 325.

[10] Valgma, I (2000). Post-stripping processes and the landscape of mined areas in Estonian oil shale open casts. Oil Shale, 17(2), 201 - 212.

[11] Valgma, I (2003). Estonian oil shale resources calculated by GIS method. Oil Shale, 20(3), 404 - 411.

[12] Valgma, I. (1999). Mapping potential areas of ground subsidence in Estonian underground oil shale mining district. In: Proceedings of the 2nd International Conference “Environment. Technology. Resources”. Rezekne, Latvia 25-27 June 1999: 2nd International Conference “Environment. Technology. Resources”. Rezekne, Latvia 25-27 June 1999. , 1999, 227 - 232.

[13] Valgma, I. (2009). Oil Shale mining-related research in Estonia. Oil Shale, 26(4), 445 - 150.

[14] Valgma, I.; Väizene, V.; Orru, M.; Vendla, S.; Ljaš, J.; Pensa, M.; Karu, V. (2014). Influence of oil shale mining on the environment in Estonia. In: Resources and energy saving: (Toim.) I. Valgma. Tallinn: Mäeinstituut, 2014.