Underground Development Research Articles

Use of an Adaptive Management System to Minimize Impacts of Deep-Sea Nodule Collection

Abstract In the nascent deep-sea mining industry, there is currently a high degree of uncertainty about what impacts prolonged metal extraction will have on the receiving environment. There is also concern regarding the transparency and monitoring of operations since the target environment is extremely remote and inaccessible. Polymetallic nodule collection is being pursued, which is distinct from other forms of deep-sea mining in that the resource is distributed in a thin layer atop the seabed, unlike cobalt-rich crusts or massive sulfides, which are concentrated in specific areas. The second distribution of nodules provides opportunities for dynamic mine planning not available for other mineral sources as many constraints normally affecting mining operations like waste stripping or underground development are absent. Also, the highly mobile ship-based collection system that utilizes robotic collectors is easily relocated to other areas in response to emerging data on environmental constraints such as proximity to fragile habitats, sensitive species, or high cumulative impacts. An adaptive management system has been identified as a vital strategy to address scientific uncertainty of ecological impacts of deep-sea mining. The design features dynamic mine planning, scenario modeling, and impact forecasting. Also, operating data will be transparently viewable in a publicly available dashboard. This paper describes an implementation of a threshold-based framework for an effective adaptive management system designed to leverage the unique characteristics inherent to the resource.

Spatial Pattern of Underground Space Development in Major Cities in China: Evaluation and Analysis

Underground space development has gradually become an organic part of China’s urban development and construction. Comprehensively developing underground space scientifically and rationally to give full play to its comprehensive benefits is the main problem faced by China’s underground space development at this stage. This research starts with the measurement of the level of urban underground space (UUS) development. This paper constructs a UUS development level measurement indicator system, which is composed of Construction of UUS (D1), urban economic development indicators (D2), and urban population development indicators (D3), which has 12 secondary indicators, and then we use entropy-TOPSIS method to quantitatively evaluate the development level of underground public space in 39 prefecture-level cities and above in my country and analyze its spatial differentiation. The results show that the urban agglomeration has the characteristics of “high-high” cluster distribution with the development level of underground space. However, the overall level of underground space development in China’s major cities is not high and there are apparent differences in the level of UUS development. In terms of spatial distribution, the sustainable development level of cities in the eastern coastal regions of China is relatively high, with towns in the central and northeastern areas ranking second and western towns and northeastern cities ranking the lowest. At the same time, we found that there is a mismatch between the underground space development index and the economic population development index in the evaluation index. Finally, some suggestions are put forward to realize the balanced development of UUS development in our country.

Explicit dynamics based numerical simulation approach for assessment of impact of relief hole on blast induced deformation pattern in an underground face blast

The exploitation of geo-resources is dominantly done using drilling and blasting. The breakage of rock mass by blasting has many challenges. The optimal breakage in an underground development face/tunnel blast is dependent on the relief area provided to the blast holes. This paper has discussed the impact of the number and diameter of the relief holes on the breakage pattern of the rock. The numerical simulation with varying numbers and diameter of relief hole was carried out for this purpose. The isosurface output from numerical simulation was plotted. The plot was used to compare the extent of deformation under varying conditions of relief holes. The analysis shows that the higher number of relief holes with optimum diameter gives more controlled deformation than single relief hole with larger diameter. The nearfield vibrations were also recorded by placement of seismographs. The waveform analysis of the recorded vibration was carried out. The redesigning of the blasting pattern was done using the results of numerical simulation and waveform analysis. The redesigned pattern consists of four relief holes of 115 mm diameter. It was found that the number of cut blast holes firing simultaneously should not be more than two in order to get the optimum breakage for the modelled condition. The blasting output with the revised design has resulted into the considerable improvements in the pull and reduction of overbreak. The revised pattern has addressed the issues of the socket formation at the site.

Study on Risk Assessment of Underground Natural Gas Storage Development

Study on Risk Assessment of Underground Natural Gas Storage Development

3D Underground Property Rights of Transportation Infrastructures: Case Study of Piraeus Metro Station, Greece

Underground development covers a wide range of underground uses, transportation and infrastructures networks; water and energy storage facilities; municipal spaces, housing, business and manufacturing facilities; and overall exploitation of Urban Underground Space (UUS). According to the Greek legal framework on properties underground, transportation networks, such as the metro, are developed deep enough that no compensation is due to surface parcel owners, which are usually a public entity. The current Greek cadastral system is two-dimensional and there are no records for underground transportation networks. As the need for the exploitation of UUS is arising, especially in densely populated Greek cities, such as Athens, the detailed documentation of transportation networks 3D underground property rights is essential. Herein is presented the technical and legal definition of the 3D underground property rights of the Piraeus Metro Station that is constructed in Piraeus Municipality UUS. Three-dimensional underground models for both Piraeus Station and official cadastral parcels are created so as to identify their 3D spatial intersection. For the identification of their legal and spatial status in 2D, the UUS was subdivided into layers in respect to the station’s vertical infrastructure and then correlated to the current cadastral 2D spatial data. The presented 3D underground property rights of Greece’s major urban underground transportation network facilitates its registration in the current 2D Greek cadastral system and contributes to the better understanding and the identification of legal and technical aspects of UUS rights in Greece.

2-D Electrical Resistivity Imaging Survey for Lithological Assessment at Igwete Primary School, Amai, South-South Nigeria

Electrical Resistivity Imaging (ERI) is a useful near-surface imaging technique, which mainly include data acquisition, numerical modelling and tomographic inversion. Within the study area, only one – dimensional (1-D) Electrical Resistivity survey has been carried out for Geophysical investigations. Therefore, 2-D ERI survey was carried out at the Igwete Primary School, Amai to provide electrical picture of the subsurface from which discrete bodies and lithology are better revealed vertically and in lateral extent. The 2-D ERT survey data were acquired using the Petrozenith Earth Resistivity meter while employing the Wenner electrode array. The 2-D apparent resistivity data were inverted to obtain true resistivities of the subsurface using res2dinv software running on personal computer. The subsurface resistivity models were displayed as pseudo sections and inverted resistivity section in the form of colour shaded contour maps. The inverse resistivity model images indicate that at a lateral extent in the range (15.00-21.00) m and (33.00-39.00) m, anomalies suspected to be gravel mixed with sand is in place with resistivities of about (254.00-948.00) Ωm. From the geologic section we can infer that a geological formation is observed at a lateral position of (27.00-32.00) m of resistivity in the range (90.00-93.00) Ωm. This structure is inferred to be a clay pocket. The sandy nature of the formation requires that underground water development be sought for at (9.00-15.00) m over a depth (2.30-8.00) m in the sandy environment. Results of 2D resistivity imaging has helped to delineate the lithology which comprise mainly of; sand, sandy clay, clayey sand depositional environment. The resistivity of these lithology falls in the range (90.00-93.00) Ωm with depth to formation of about (2.30-6.00) m.

Analytical solutions for the design of shotcreted waste rock barricades to retain slurried paste backfill

Over the past decades, filling underground mined-out openings (stopes) with slurried backfills has witnessed a significant growth in the mining industry. To do so, retaining structures frequently called barricades should be built in access drifts near draw points to keep the slurried filling materials in place. Barricades made of waste rock (often produced from underground development) are constructed in a more convenient and sustainable manner at lower cost, compared to traditional barricades made of high-strength man-made materials. In recent years, a few analytical solutions have been developed for sizing waste rock barricades (WRB) based on limit-equilibrium analysis. These solutions correspond to such cases when there are no reinforcements made to WRBs except for compaction. A full cover of the entire surface of downstream slope may result in poor drainage and built-up of high pore water pressures behind WRB. Shotcrete is thus usually sprayed over the upper part. More commonly, when constructing a WRB, shotcrete is sprayed on the downstream slope over the upper part (about one third) of a barricade to promote its stability as a whole and to prevent local failures at the barricade top, especially for a WRB with limited top length. To take this aspect into account, new analytical solutions are proposed here to design the integrated backfill barricade built with waste rock and shotcrete. The proposed solutions can be used to estimate the dimensions of shotcreted WRB and strength of shotcrete. An instability criterion, based on the first occurrence among displacement jump of the barricade top or coalescence of currently yield zones, is introduced to help judge the onset of instability of a shotcreted WRB structure. The validity and predictivity of the proposed analytical solutions were calibrated and verified using numerical simulations. Sample calculations are also conducted to illustrate the shotcreted WRB design (i.e., required cohesion and top length) by considering global and local stability. The proposed solutions correlate well with numerical simulations for representative stope height, barricade and shotcrete geometries and properties of waste rocks and shotcrete. The proposed solutions can thus be used to evaluate the required cohesion cs and top length LSL of shotcrete, based on the global and local stability analysis. The proposed solution can also be used to estimate the size of WRB when the parameters of shotcrete are known.

Use of Tree-Based Machine Learning Methods for Stratigraphic Classification in 3D Geological Modelling

The need for underground development has been expanded due to rapid urbanization and to reduce the negative impact on city living. In recent years, 3D geological modelling has been widely used by engineers and geo-scientists for desk study and has shown its capability of integrating geological and geotechnical information for better usage in building and civil engineering projects. To provide techniques and instruction(?), a 3D Geo-data Modelling and Management System (GeM2S) has been established to better understand the subsurface conditions in Singapore. However, the geological stratum between the existing boreholes is often not investigated, which brings the possibility of vital errors in underground design due to inaccurate interpretation of the ground conditions. It is desirable to utilize advanced machine learning methods to predict and update the 3D geo-models. Machine learning is regarded as a subset in the field of artificial intelligence, which has shown its rapid development recently. However, the accuracy of the model is one of the major concerns when the techniques are applied. In this study, four machine learning models are proposed to provide the solutions for stratigraphic classification, namely, Random Forest (RF), Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), and Categorical Boosting (Catboost). The borehole data are located in the Bishan planning region in Singapore. The voxel-based input data for the models are spatial coordinates (X, Y, Z) and ground surface elevation. The prediction results demonstrate that LightGBM with optimization have produced the highest performance in this multi-classification problems. Finally, based on the prediction results of LightGBM, the voxel-based 3D geological models and the selected cross-sections are built for further analysis and comparison.

Compensation Appraisal of Partial Takings for Underground Development Project

도시개발이 농지나 임야 같은 미개발지를 도시용지로 전환하는데 그치지 않고, 기존 도시용지를 입체적으로 개발하는 것으로 확대되고 있으며, 주요 대상은 지하공간의 개발이다. 지하공간 개발의 확대는 보다 안전하고 쾌적한 환경을 원하는 사회적 요구를 반영한 것이다. 이와 연계되어 지하공간의 부분사용에 대한 감정평가의 중요성 또한 증가하고 있다. 하지만 지하공간에 대한 사용권원 확보를 위한 감정평가 기준은 지난 수 십년 동안 거의 바뀌지 않았다. 이와 관련하여 다음과 같은 개선 노력이 필요하다. 첫째, 『토지보상법』과 하위 법령의 개정을 통해 사용보상에 대한 통일된 평가원칙과 기준을 수립하는 것이다. 물리적 제약을 의미하는 입체이용저해율(지역구분, 입체이용률, 한계심도, 심도별 효용차이 등) 적용뿐만 아니라 경제적 가치하락을 야기하는 (-) 외부효과까지 고려되도록 해야 한다. 다만, 개별사업의 유형, 규모, 설치 위치 등에 따라 세부적으로 구분할 필요가 있다. 둘째, 사용권원 확보를 위한 보상에 있어 객관성과 공정성을 확보하기 위해 감정평가 관련 지표를 독립적이고 체계적으로 마련할 필요가 있다. 전기, 수도, 철도 사업 등에 있어 정부는 ‘사업시행자’ 위치에 있다. 사업시행자가 보상의 기준을 정하는 것은 정당보상의 원칙을 훼손하는 것으로, 보상 관련 기준을 감정평가업계가 독립적으로 마련할 수 있도록 하는 할 필요가 있다. 셋째, 감정평가업계는 객관적 논리와 수치에 기반하여 일반국민들이 쉽게 수긍할 수 있는 합리적 감정평가기준을 마련할 필요가 있다. 지가상승으로 지하공간 활용이 확대되는 추세에 맞게 한계심도를 현재보다 깊게 설정하고, 지하시설물로 인한 장래 이용제약에 대한 보상개념 등을 재정립할 필요가 있다. 이 과정에서 추가보정률의 개념과 성격을 명확히 정립하고, 합리적 수준으로 요율을 마련할 필요가 있다.

Underground Mining Technology and Development Trend of Underground Mining

Underground Mining Technology and Development Trend of Underground Mining

Underground space development resulting from increased urban migration

Worldwide urbanization has resulted in the creation of so called “megacities” with populations of 10 million or more. It is estimated that 68% of the world’s population will reside in urban centers by the year 2050 up from 55% in 2018 [1]. This pace of urbanization is staggering, especially in China where urban populations have more than doubled over the last 30 years, while urban land extent has more than tripled [2]. Today, urban planners and engineers are faced with challenging decisions regarding land management planning. To manage this population increase, there is a need to cultivate urban underground space to reduce congestion on the surface, control urban sprawl, and provide opportunities to re-purpose land for recreational space. This discussion paper provides a review of several recommended practices for urban underground space development addressing planning, intended function, and environmental sustainability/resiliency.

Application of SfM-MVS for mining geology: Capture set-up and automated processing using the Dugald River Zn-Pb-Ag mine as a case study

The use of structure-from-motion, multi-view stereo (SfM-MVS) in the mining industry is well-established for capturing digital data on surface. However, the application of SfM-MVS in active underground mining has received less attention as there are unique challenges that need to be overcome, especially if a procedure is to be applied daily in active mining. Unique challenges include preparation time, camera positioning, illumination and useability. The faces of active development drives are generally only available for a short period before prepared and blasted, thus information is lost if not mapped immediately. Furthermore, due to safety concerns, unsupported faces cannot be approached for physical mapping. SfM-MVS allows these faces to be viewed and mapped in the form of a virtual outcrop, thus, allowing for remote mapping of underground development, which at the Dugald River mine, located in Queensland, Australia, allowed for mapping continuity as staff worked remotely during COVID-19. This contribution describes how to set-up a capture in an underground mine to produce high-quality SfM-MVS 3D reconstructions of development faces. The methodology can be readily incorporated into a standard operating procedure. While the procedure can be used with most photogrammetry software packages that utilise SfM-MVS algorithms, it is best utilised using the provided Python script and Agisoft Metashape Professional v1.6. The script allows for automation of capture processing, which can free up several hours per day compared to user-interacted processing.

Efficiency of mineral additives to binding component for making hardening mixtures at underground operations

For effective operation of mining enterprises, including mines of ferrous metallurgy, supply of quality binding components is necessary to make hardening mixtures for packing of goave, aroused at underground development of hard mineral deposits. Results of the study of compositions based on ash-cement, nepheline, belit-aluminates and lime binding component made of mining and metallurgical production wastes presented. Application of vibro-, mechanical- and electrochemical activation methods to obtain filling mixtures from local low-quality raw materials, as well as activation of binding components were analyzed. A model to evaluate efficiency of binding additives presented. It was shown that decrease of cement consumption by addition of binding components of mineral origin requires perfection of mining processes, first of all, grinding and activation. It was proved, that additions of electric filters ash, nephelines, belit-aluminates and lime, obtained by utilization of current and old tailings to the basic binding component – portland cement – makes it possible to obtain hardening filling mixtures, having high enough strength to apply them at goave packing. Application of the study results makes it perspective for depressed mining and related enterprises to survive under conditions of the forming market.

Exploiting a Semi-Automatic Point Cloud Segmentation Method to Improve the Quality of Rock-Mass Characterization. The Cima Grappa Conservative Restoration Case Study

This paper presents results from applying semi-automatic point cloud segmentation methods in the underground tunnels within the Military Shrine’s conservative restoration project in Cima Grappa (Italy). The studied area, which has a predominant underground development distributed in a network of tunnels, is characterized by diffuse rock collapsing. In such a context, carrying out surveys and other technical operations are dangerous activities. Considering safety restrictions and unreachable impervious tunnels, having approached the study area with the scan-line survey technique resulted in only partial rock mass characterization. Hence, the geo-mechanical dataset was integrated, applying a semi-automatic segmentation method to the point clouds acquired through terrestrial laser scanning (TLS). The combined approach allowed for remote performance of detailed rock mass characterization, even remotely, in a short time and with a limited operators presence on site. Moreover, it permitted extending assessing tunnels’ stability and state of conservation to the inaccessible areas.

Rock pressure control methods based on detected regularities of stress formation in mining structures

Relevance. Subsurface mining at the Gaysky ore mine is intensifying because of the growing need in raw material. It leads to rapid increase in the depth of mining and to problems connected with the stability of mining system constructive elements. The effi ciency of the Gaysky deposit underground development is largely determined by mining system constructive elements stability. Ore cave-in in the chambers of the fi rst and second stages causes the growth of load in the interchamber pillars leading to their collapse, loss of boreholes and development headings. Mining productivity in the chambers of the fi rst, second, etc. stages falls, oversize yield grows, which also impairs the effectiveness of mining. Hanging wall and footwall cave-in in the deposit under consideration may be explained not only by host rock poor stability, but also by the presence of high compressive tectonic stresses, that were determined by the authors. Stress measurements in the rock mass have shown that the east-west stresses have doubled the northsouth stresses and have been 1.5 times as high as the vertical ones. The purpose of the research is to reduce stresses in stopes ore in place when excavating steeply dipping ore bodies using a sublevel stoping method with a hardening backfi ll. Research methodology includes full-scale experimental measurements of the stress state of the rock mass and ore in place at accessible depths and horizons of the deposit. A comprehensive scientifi c research method was used, including the analysis and theoretical generalization of stress distribution regularities in the arrays of the extracted chamber reserves and mathematical modeling of the behavior of the research object; theoretical results were compared with the results of instrumental observations. The analysis of the research results made it possible to establish the stress-strained state behavior in the course of mining. It was revealed that when mining a deposit using sublevel stoping, the most loaded elements are the hanging wall and footwall exposed parts, ceiling, interchamber pillars and bottom. Therefore, it is necessary to take measures to increase ore in place stability in order to guarantee the safety and effi ciency of the mineral extraction technology. Conclusions. Relieve slots method is among the most effective and frequently used active method of rock mass pressure control. The method has come into common use because it is easy to apply. Main labor inputs of a relieve slot creation are only reduced to extra drilling and blasting which do not require additional tunnel driving. The aim of the relieve slot is to create additional free surfaces for deformation, to redistribute rock mass stress-strain state, and remove stress from the protected element of the mining system.

Doing away with blasting in underground development: a collaboration with Vale and Komatsu-CMIC

No Abstract.

Enhancing underground development users’ health through facilities management: a study of the underground metro system in Hong Kong

The ever-rising global population poses a great challenge for cities to accommodate additional citizens in limited land space. As such, many high-density cities were transforming the mind from “build higher” to “dip deeper”. However, most of the existing underground space were built with inadequate consideration of user’s health. Thus, this study aims to enhance underground users’ health using an integrated Facilities Management-Health (FM-H) model. A questionnaire survey study was conducted in 4 underground metro stations in Hong Kong, which resulted in 120 valid survey responses. Based on the extensive literature review, the survey was designed to cover eight FM factors: thermal comfort, indoor air quality, ventilation, visual comfort, noise level, greenery, wayfinding support, and immediate access, and four health indicators: physical health, emotional exhaustion, depersonalization and claustrophobia stress. Pearson’s correlation and multiple regression modelling were adopted to investigate the associations between FM and users’ health. The results indicate that, even though all FM factors were found to have a significant impact to at least one health indicator, thermal comfort and wayfinding support were found to have impacted on three health indicators respectively. This sheds light to the importance of needing further investigation into these two FM factors in underground studies.

Re-promoting Sustainable Underground Urbanization for Developed and Developing Countries in Our Modern History

During recent decades of overwhelming exploration of underground resources (groundwater, geothermal energy, minerals) and underground spaces (tunnels, caverns, buildings), there has been a lack of in-deep investigation on international agenda to look at the degree of political awareness of sustainable underground development. International organizations advocating and debating the use of underground space and its innovative contribution to urban futures, have been sustained through intensive interaction through conferences and working groups. These active moves involved public and private actors from developed and developing countries, with a rapidly increasing interest to explore the various and viable usage of this natural resource – subsurface space. From 2014 to present, as an international consensus built up by a long-term advocating efforts addressed through a series of World Urban Forums, United Nations Human Settlements Program (UN-HABITAT) recognized the necessity of promoting best practices of the sustainable use of underground space for resilient urban development in modern era and for implementing the 17 Sustainable Development Goals (SDGs) of UN 2030 Agenda. This article will present a first retrospect on the modern history of research initiation and international promotional agenda for sustainable underground urbanization. Qualitative archive data analysis and city case study demonstration will be used to showcase international stakeholders’ awareness enhancement, policy promotion and universal implementation.

Prediction of Underground Space Development Function of Existing Industrial District in City Based on CA-Markov Model

Scientific analysis of the spatial evolution of existing industrial areas in cities and prediction of future development needs will help to rationally allocate land resources in existing industrial areas in urban renewal, scientifically and rationally develop underground space, and promote the sustainable development of existing industrial areas. First of all, the development mode and leading function type of the existing industrial zone in the city are sorted out, and its corresponding underground space development function is further sorted out. It is found that the underground space development of the existing industrial zones in the city is closely related to the dominant functions and location of the ground renewal. To scientifically guide the development of underground space in existing industrial areas in cities, this study proposes a method based on the dynamics model and the CA-Markov model to predict the functions of underground space development in existing industrial areas in cities, which will improve the efficiency and Benefits to promote the rational allocation of land resources is of great significance.

Suitability evaluation of underground space development in Dalian

Rational development and utilization of urban underground space has become an important measure to alleviate the contradiction between supply and demand of land resources, improve urban capacity and optimize urban layout. Underground space is an important part of the geological environment because of its natural resources. Unreasonable development will lead to geological environment problems. In this paper, combined with the actual situation of Dalian City, on the basis of comprehensive analysis of geological environment conditions, eight indicators are selected from the aspects of topography, engineering geological conditions, hydrogeological conditions, geological hazards, ecological factors and human activities to construct the hierarchy model of suitability evaluation for underground space development in Dalian City. The analytic hierarchy process and comprehensive index method are applied to the evaluation. The results show that: the suitable area, secondary suitable area, less suitable area and unsuitable area are 3812.58km2, 5430.91km2, 2711.38km2 and 1659.06km2, accounting for 28.00%, 39.89%, 19.92% and 12.19% respectively. The evaluation results can provide the basis for the future development and utilization planning of underground space in Dalian city.