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英文文獻 Roadheader applications in mining and tunneling industries H. Copur1, L. Ozdemir2, and J. Rostami3 1Graduate Student, 2 Director and Professor, and 3 Assistant Professor Earth Mechanics Institute, Colorado School of Mines, Golden, Colorado, 80401 ABSTRACT Roadheaders offer a unique capability and flexibility for the excavation of soft to medium strength rock formations, therefore, are widely used in underground mining and tunneling operations. A critical issue in successful roadheader application is the ability to develop accurate and reliable estimates of machine production capacity and the associated bit costs. This paper presents and discusses the recent work completed at the Earth Mechanics Institute of Colorado School of Mines on the use of historical data for use as a performance predictor model. The model is based on extensive field data collected from different roadheader operations in a wide variety of geologic formations. The paper also discusses the development of this database and the resultant empirical performance prediction equations derived to estimate roadheader cutting rates and bit consumption. INTRODUCTION The more widespread use of the mechanical excavation systems is a trend set by increasing pressure on the mining and civil construction industries to move away from the conventional drill and blast methods to improve productivity and reduce costs. The additional benefits of mechanical mining include significantly improved safety, reduced ground support requirements and fewer personnel. These advantages coupled with recent enhancements in machine performance and reliability have resulted in mechanical miners taking a larger share of the rock excavation market. Roadheaders are the most widely used underground partial-face excavation machines for soft to medium strength rocks, particularly for sedimentary rocks. They are used for both development and production in soft rock mining industry (i.e. main haulage drifts, roadways, cross-cuts, etc.) particularly in coal, industrial minerals and evaporitic rocks. In civil construction, they find extensive use for excavation of tunnels (railway, roadway, sewer, diversion tunnels, etc.) in soft ground conditions, as well as for enlargement and rehabilitation of various underground structures. Their ability to excavate almost any profile opening also makes them very attractive to those mining and civil construction projects where various opening sizes and profiles need to be constructed. In addition to their high mobility and versatility, roadheaders are generally low capital cost systems compared to the most other mechanical excavators. Because of higher cutting power density due to a smaller cutting drum, they offer the capability to excavate rocks harder and more abrasive than their counterparts, such as the continuous miners and the borers. ROADHEADERS IN LAST 50 YEARS Roadheaders were first developed for mechanical excavation of coal in the early 50s. Today, their application areas have expanded beyond coal mining as a result of continual performance increases brought about by new technological developments and design improvements. The major improvements achieved in the last 50 years consist of steadily increased machine weight, size and cutterhead power, improved design of boom, muck pick up and loading system, more efficient cutterhead design, metallurgical developments in cutting bits, advances in hydraulic and electrical systems, and more widespread use of automation and remote control features. All these have led to drastic enhancements in machine cutting capabilities, system availability and the service life. Machine weights have reached up to 120 tons providing more stable and stiffer (less vibration, less maintenance) platforms from which higher thrust forces can be generated for attacking harder rock formations. . The cutterhead power has increased significantly, approaching 500 kW to allow for higher torque capacities. Modern machines have the ability to cut cross-sections over 100m2 from a stationary point. Computer aided cutterhead lacing design has developed to a stage to enable the design of optimal bit layout to achieve the maximum efficiency in the rock and geologic conditions to be encountered. The cutting bits have evolved from simple chisel to robust conical bits. The muck collection and transport systems have also undergone major improvements, increasing attainable production rates. The loading apron can now be manufactured as an extendible piece providing for more mobility and flexibility. The machines can be equipped with rock bolting and automatic dust suppression equipment to enhance the safety of personnel working at the heading. They can also be fitted with laser-guided alignment control systems, computer profile controlling and remote control systems allowing for reduced operator sensitivity coupled with increased efficiency and productivity. Figure-1 shows a picture of a modern transverse type roadheader with telescopic boom and bolting system. Mobility, flexibility and the selective mining capability constitute some of the most important application advantages of roadheaders leading to cost effective operations. Mobility means easy relocation from one face to another to meet the daily development and production requirements of a mine. Flexibility allows for quick changes in operational conditions such as different opening profiles (horse-shoe, rectangular, etc.), cross-sectional sizes, gradients (up to 20, sometimes 30 degrees), and the turning radius (can make an almost 90 degree turn). Selectivity refers to the ability to excavate different parts of a mixed face where the ore can be mined separately to reduce dilution and to minimize waste handling, both contributing to improved productivity. Since roadheaders are partial-face machines, the face is accessible, and therefore, cutters can be inspected and changed easily, and the roof support can be installed very close to the face. In addition to these, high production rates in favorable ground conditions, improved safety, reduced ground support and ventilation requirements, all resulting in reduced excavation costs are the other important advantages of roadheaders. The hard rock cutting ability of roadheaders is the most important limiting factor affecting their applications. This is mostly due to the high wear experienced by drag bits in hard, abrasive rocks. The present day, heavy-duty roadheaders can economically cut most rock formations up to 100 MPa (~14,500 psi) uniaxial compressive strength (UCS) and rocks up to 160 MPa (~23,000 psi) UCS if favorable jointing or bedding is present with low RQD numbers. Increasing frequency of joints or other rock weaknesses make the rock excavation easier as the machine simply pulls or rips out the blocks instead of cutting them. If the rock is very abrasive, or the pick consumption rate is more than 1-pick/m3, then roadheader excavation usually becomes uneconomical due to frequent bit changes coupled with increased machine vibrations and maintenance costs. A significant amount of effort has been placed over the years on increasing the ability of roadheaders to cut hard rock. Most of these efforts have focused on structural changes in the machines, such as increased weight, stiffer frames and more cutterhead power. Extensive field trials of these machines showed that the cutting tool is still the weakest point in hard rock excavation. Unless a drastic improvement is achieved in bit life, the true hard rock cutting is still beyond the realm of possibility with roadheaders. The Earth Mechanics Institute(EMI) of the Colorado School of Mines has been developing a new cutter technology, the Mini-Disc Cutter, to implement the hard rock cutting ability of disc cutters on roadheaders, as well as other types of mechanical excavators (Ozdemir et al, 1995). The full-scale laboratory tests with a standard transverse cutterhead showed that MiniDisc Cutters could increase the ability of the roadheaders for hard rock excavation while providing for lesser cutter change and maintenance stoppages. This new cutting technology holds great promise for application on roadheaders to extend their capability into economical excavation of hard rocks. In addition, using the mini-disc cutters, a drum miner concept has been developed by EMI for application to hard rock mine development. FIELD PERFORMANCE DATABASE Performance prediction is an important factor for successful roadheader application. This deals generally with machine selection, production rate and bit cost estimation. Successful application of roadheader technology to any mining operation dictates that accurate and reliable estimates are developed for attainable production rates and the accompanying bit costs. In addition, it is of crucial importance that the bit design and cutterhead layout is optimized for the rock conditions to be encountered during excavation. Performance prediction encompasses the assessment of instantaneous cutting rates, bit consumption rates and machine utilization for different geological units. The instantaneous cutting rate (ICR) is the production rate during actual cutting time, (tons or m3 / cutting hour). Pick consumption rate refers to the number of picks changed per unit volume or weight of rock excavated, (picks / m3 or ton). Machine utilization is the percentage of time used for excavation during the project Table-I: Classification of the Information in the Database INFORMATION GROUP DETAILS General Information Type/purpose of excavation (roadway, railway, sewer, mining gallery, etc.), contractor, owner, consultant, location, starting and completion date, etc. Roadheader Information Manufacturer, condition of the roadheader (new, refurbished, direct reuse), specifications of roadheader, machine weight, cutterhead power and diameter, bit number and type, ancillary equipment (automatic profile control, water sprays, grippers, etc.) Technical and Operational Information Excavation length, depth, and gradients, dimensions of excavation profile, operator experience, cutting sequence at the face, daily and weekly mining hours, muck evacuation system, ground support system, etc. Rock Mass Information For Each Rock Zone Geological origin, number and character of geological zones, hydrogeological conditions, rock mass classifications, RQD, bedding properties, joint set properties (orientation, spacing, roughness, filling, etc.) Intact Rock Information For Each Rock Zone Rock cuttability properties, uniaxial and tensile strength, elasticity modulus, surface hardness, texture (porosity, mineral / quartz content & grain sizes, microfractures, etc.), abrasivity properties, etc. Performance Records For Each Rock Zone Cutting rates, bit and holder consumption, roadheader utilization and availability, energy consumption, average and best advance rates (shiftly/daily/weekly/monthly), major obstructions to excavation operation, downtime analysis (roadheader related stoppages, backup system stoppages, ground and support stoppages, etc.) The Earth Mechanics Institute of the Colorado School of Mines jointly with the Mining Department of the Istanbul Technical University has established an extensive database related to the field performance of roadheaders with the objective of developing empirical models for accurate and reliable performance predictions. The database contains field data from numerous mining and civil construction projects worldwide and includes a variety of roadheaders and different geotechnical conditions. The empirical performance prediction methods are principally based on the past experience and the statistical interpretation of the previously recorded case histories. To obtain the required field data in an usable and meaningful format, a data collection sheet was prepared and sent to major contractors, owners, consultants, and roadheader manufacturers. In addition, data was gathered from available literature on roadheader performance and through actual visits to job sites. This data collection effort is continuing. The database includes six categories of information, as shown in Table-I. The geological parameters in the database consist generally of rock mass and intact rock properties. The most important and pertinent rock mass properties contained in the database include Rock Quality Designation (RQD), bedding thickness, strike and dip of joint sets and hydrological conditions. The intact rock properties are uniaxial compressive strength, tensile strength, quartz content, texture and abrasivity. The rock formations are divided into separate zones to minimize the variations in the machine performance data to provide for more accurate analysis. This also simplifies the classification of the properties for each zone and the analysis of the field performance data. The major roadheader parameters included are the machine type (crawler mounted, shielded), machine weight, cutterhead type (axial, transverse), cutterhead power, cutterhead-lacing design, boom type (single, double, telescopic, articulated), and the ancillary equipment (i.e.grippers, automatic profiling, laser guidance, bit cooling and dust suppression by water jets, etc.). The operational parameters generally affect the performance of the excavator through machine utilization. The most important operational parameters include ground support, back up system (transportation, utility lines, power supply, surveying, etc.), ground treatment (water drainage, grouting, freezing, etc.), labor (availability and quality), and organization of the project (management, shift hours, material supply, etc.). CONCLUSIONS The evaluation and analysis of the data compiled in the roadheader field performance database has successfully yielded a set of equations which can be used to predict the instantaneous cutting rate (ICR) and the bit consumption rate(BCR) for roadheaders. A good relationship was found to exist between these two parameters and the machine power (P), weight (W) and the rock compressive strength (UCS). Equations were developed for these parameters as a function of P, W and UCS. These equations were found mainly applicable to soft rocks of evaporatic origin. The current analysis is being extended to include harder rocks with or without joints to make the equations more universal. In jointed rock, the RQD value will be utilized as a measure of rock mass characteristics from a roadheader cuttability viewpoint. It is believed that these efforts will lead to the formulation of an accurate roadheader performance prediction model which can be used in different rock types where the roadheaders are economically applicable. 中文譯文 掘進機在采礦和隧道業(yè)中的應用 摘要 掘進機為方便的挖掘硬巖而提供了一個獨特的能力。因此，廣泛地被用于地下，采礦和隧道掘進。在成功使用掘進機方面的一個具有決定性的議題是提高機器生產率和降低采掘成本的可靠性分析。這篇文章提出并且討論科羅拉多學校地球力學研究會最近完成的工作對于挖掘在歷史上的使用數(shù)據(jù)當作一個動態(tài)的性能模型。這個模型是從不同的掘進機在各式各樣的地質條件下工作為基礎來廣泛收集的數(shù)據(jù)。這篇文章也討論這一數(shù)據(jù)庫的發(fā)展和含量被源自估計掘進機的截割率和截割頭能耗的預測為程序。 介紹 目前，機械挖掘系統(tǒng)廣大的使用在采礦和市政建造行業(yè)上，主要的趨勢是提高生產率和減低成本。這些主要的好處就是減少了土地的占有量；同時，增強了工人的安全性。這些優(yōu)點主要取決于機器性能的大幅度提高，這些可靠性已經造成采掘市場的擴大，并且工人的水平得到了提高。 掘進機是一種廣泛應用在地下軟硬巖石的挖掘上的機器，特別是對于那些沉積巖。他們用在軟巖采礦行業(yè)的生產和發(fā)展（也就是，巷道掘進、支護，打洞，等等）。特別是用在煤礦，礦山上。在市政建設中，經常使用在較軟地面的管道開掘（鐵路、公路、排水溝、導流管道等等）。連同于擴大巷道或者地下結構的復原。而且掘進機的應用能力非常廣泛，基本可以挖掘任何結構和斷面的尺寸，不管巷道斷面有復雜，都能滿足人們的需求。因此，受到人們的一致歡迎。 除了那些高的機動靈活性和適應性之外，掘進機另外一個最大的優(yōu)點就是成本低廉，經濟性好。一般的掘進機都有很大的功率，但卻是通過電磁方便的控制。因此，與其他機器相比，它能夠較好的掘進硬巖和粉碎。例如連續(xù)開采和挖掘。 掘進機近50年的發(fā)展 掘進機最初的使用是在上世紀50年代煤礦的開采中。今天，在科技高速發(fā)展的推動下，人們設計的掘進機性能和其他方面都有了很大的進步，它們的應用已經遠遠超過了煤炭開采的范圍。主要的改進發(fā)生在最近這50年。包括，機器的重量和尺寸比以往增大了很多，截割頭功率加大、支護桿，耙抓機構和控制系統(tǒng)都得到了很大的改進。高效率截割頭的設計，高截割率截割齒的發(fā)展，高壓水射流輔助截割，電液一體化，較大地方使用自動控制系統(tǒng)以及根據(jù)不同地質條件間接控制。所以的這些都使機器的截割能力、工作效率、功率等都得到了長足的提高。 機器的重量已經高達120噸左右，那樣接地比壓也得到提高。使機器更加穩(wěn)定和堅固，那么，在截割較硬的巖石時，面對大的沖擊機器仍然能保證較少的振動，維修率降低。目前，掘進機的功率可達到500KW左右，使扭矩得到提高?，F(xiàn)在的機器截割斷面可達到100m2。采用計算機輔助設計，使截割頭的布置可達到一個最佳點切入巖石表面，那樣的話截割頭的工作效率達到最佳狀態(tài)。截齒已經從簡單的鉆發(fā)展到了錐形。煤巖裝載機構和轉運機構也得到了很大的進步，可達到生產率的要求。中間輸送機現(xiàn)在被制造成可伸縮式，使結構簡單化，裝運方便。前面裝有防護設施，使截割下來的巖石以及截割過程中產生的粉塵擋在外面，保證了操作人員的安全。掘進機也能配備激光指導的對準控制系統(tǒng)，由計算機先分析出最佳的截割輪廓，如果按照此順序截割的話，截割效率和生產力都有成提高。 普遍性、良好的控制性、和選擇性的采礦能力是掘進機發(fā)展中需要大力改進的因素，普遍性即指我們設計的掘進機能夠適應大多數(shù)礦山發(fā)展的需要。良好的控制性就是機器在過載時能夠自動保護，這樣不至于燒損機器。部分尺寸，擺角，（上擺角可達20度，下擺角可達30度）?；剞D半徑幾乎能達到90度。選擇性指的是在不同的工作環(huán)境下可以采取不同的截割功率挖掘礦石的能力，兩者能夠極大的改進生產率。因為，我們所指的掘進機是部分斷面掘進機，可以接近斷面，因此，可以很容易的調整刀頭，并且頂板架能夠很方便地接近頂面。除了這些之外，高的生產率也取決于巖石的內部特性。合理的改進通風設備，降低地表的壓力，所有的這些都可以降低成本，提高生產率。 切削硬巖的能力是影響掘進機應用的最重要因素。這可能是由于在切割尖而硬的巖石時截齒的磨損非常厲害。目前，如果采用良好的連接和配套設備，主軸的抗壓強度能達到100MPa。最大轉矩也提高了很多。 當巖石是脆性巖，巖石是在截割的時候崩落下來的而不是挖掘下來的，那么，就使采掘變的相當容易。如果巖石是粘性的或者單位能耗超過一時，那么掘進的挖掘就變的很不經濟，還可能導致機器振動加大，維修費用成倍增加。 一個很重要的量，關于增加掘進機截割硬巖的能力被放置了很多年。這些年人們都把主要精力放在機器結構方面的改進上。例如，增加重量，截割頭功率等。通過這些機器廣泛的現(xiàn)場試驗表明，截割工具仍然是截割硬巖時最大的弱點。除非一個很大的進步就是在截割時增加截齒的壽命，因此，對于掘進機而言，截割硬巖還是一個難題?？屏_拉多學校地理力學研究會已經發(fā)現(xiàn)了一種新的切削技術：錐形截割頭。這種截割頭實現(xiàn)了圓盤切削時提高截割硬巖的能力。用這種橫的截割頭在實驗室試驗出，當用較少的截齒時它的截割能力比一般的截齒大了很多，這種新的切割技術應用在掘進機上，為經濟性的截割硬巖帶來了希望。除此之外，使用這種截齒，一種新的開采技術已經被申請，為截割硬巖的發(fā)展起到很大的促進作用。 實驗數(shù)據(jù) 性能預測是掘進機應用成功的一個重要因素。這通常取決于機器的選擇，生產率，和掘進時的消耗。掘進機的技術對于任何的采掘命令，準確而可靠的估計是達到生產率的保證。除此之外，在采掘過程中，它也是對掘進路線設計，截割頭掘進巖石表面狀態(tài)的最佳選擇。性能預測也是不同地質條件下截割率、截齒消耗率、機器損耗率的表現(xiàn)。截割率單位時間截割的煤巖量，單位能耗指的是在截割單位面積或質量的煤巖所耗的電量。機器利用率是指在計劃期間作為挖掘時間所用的百分率。 科羅拉多學校的地球力學學會與其他一些有關這方面技術的大學，已經建立了正確而可靠的性能預測發(fā)展經驗模型。通過這個模型，在挖掘過程收集了廣泛的數(shù)據(jù)，組建成一個數(shù)據(jù)庫。這個數(shù)據(jù)庫收集了來自全世界多數(shù)采礦和市政建設過程中不同的地質條件下所得的挖掘數(shù)據(jù)。 表-1數(shù)據(jù)庫中的數(shù)據(jù) 數(shù)據(jù)組 內 容 基本數(shù)據(jù) 采掘目的（修路、鐵路、管道修建、排水渠、采礦巷道等等）承包人、顧問、開工和完成日期等等。 掘進機數(shù)據(jù) 制造商，掘進機概況（新的、直接重復使用）掘進機說明書，重量，截割頭直徑，電力控制，截齒數(shù)量和型式，輔助設備（內外噴霧設施，自動輪廓控制，等等）。 技術和操作上數(shù)據(jù) 掘進長度，深度和梯度，挖掘斷面，操作者經驗，每日和每周的采掘量，煤巖裝載形式，頂板支護。等等 動過的巖石區(qū)的數(shù)據(jù) 地質學區(qū)，巖石質量分類，地質學起源，水文地質學狀況，（定向，結構高度，粗度等等。） 每個巖石區(qū)的尚未被人碰過的巖石數(shù)據(jù) 巖石可截割特性，抗拉強度，柔性率，表面硬度，紋理（多孔，礦物石英含量。顆粒大小，等等）沖蝕度特性 每個巖石區(qū)的性能記錄 截割率，截齒損耗量，掘進機利用和可用性，平均和最好的超前率（變化/每日，每周，每月）主要挖掘障礙物，停工時間分析，等等。 經驗的性能預測方法主要地以先前記錄的數(shù)據(jù)和過去的經驗和統(tǒng)計為基礎。為了以一個可使用的和意義深長的圖紙幅面獲得必需的磁場數(shù)據(jù)，一個數(shù)據(jù)的收集從準備到送至主修收縮器，還有掘進機的制造商。除此之外數(shù)據(jù)收集來以后，還要經過優(yōu)化處理，這是對數(shù)據(jù)收集的繼續(xù)。 數(shù)據(jù)庫包含六種數(shù)據(jù)，如表-1所示。在數(shù)據(jù)庫的地質學特性里通常有巖石質量和尚未被人們碰過的巖石特性。被包含在數(shù)據(jù)庫的最重要的和最相關的巖石質量特性含巖石性質指示 (RQD), 固定聯(lián)合組和水文學狀態(tài)的厚度山。 尚未被人碰過的巖石特性是單橋的抗壓強度，抗拉強度，石英含量，紋理。巖石形成被區(qū)分開，使最小在機器性能數(shù)據(jù)的變化范圍提供正確的分析。這也為每個區(qū)性能數(shù)據(jù)分析單一化分類。結論：通過這些評估和數(shù)據(jù)分析，數(shù)據(jù)庫已經成功的產生能夠為掘進機預測瞬時截割率和截齒損耗率的一組方程。這些方程被發(fā)現(xiàn)主要適用于起源的軟巖，現(xiàn)在的分析是詳細化的，可以通用的，含有很多復雜的巖石，使程序變的更萬用。在有裂縫的巖石中，這種分析將會被利用來自一個掘進機的可截割性觀點對巖石特性的衡量。所以，我們可以認為，這些努力將會作為掘進機在不同的巖石類型中實現(xiàn)經濟截割的性能預測公式。