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一臺(tái)螺旋鉆采煤機(jī)設(shè)計(jì)
翻譯部分
英文原文
High Productivity —A Question of Shearer Loader Cutting Sequences
K. Nienhaus, A. K. Bayer & H. Haut, Aachen University of Technology, GER
1 Abstract
Recently, the focus in underground longwall coal mining has been on increasing the installed motor power of shearer loaders and armoured face conveyors (AFC), more sophisticated support control systems and longer face length, in order to reduce costs and achieve higher productivity. These efforts have resulted in higher output and previously unseen face advance rates. The trend towards “bigger and better” equipment and layout schemes, however, is rapidly nearing the limitations of technical and economical feasibility. To realise further productivity increases, organisational changes of longwall mining procedures looks like the only reasonable answer. The benefits of opti-mised shearer loader cutting sequences, leading to better performance, are discussed in this paper.
2 Introductions
Traditionally, in underground longwall mining operations, shearer loaders produce coal using either one of the following cutting sequences: uni-directional or bi-directional cycles. Besides these pre-dominant methods, alternative mining cycles have also been developed and successfully applied in underground hard coal mines all over the world. The half-web cutting cycle as e.g. utilized in RAG Coal International’s Twentymile Mine in Colorado, USA, and the “Opti-Cycle” of Matla’s South African shortwall operation must be mentioned in this context. Other mines have also tested similar but modified cutting cycles resulting in improved output, e.g. improvements in terms of productiv-ity increases of up to 40 % are thought possible。
Whereas the mentioned mines are applying the alternative cutting methods according to their spe-cific conditions, –e.g. seam height or equipment used, –this paper looks systematically at the differ-ent methods from a generalised point of view. A detailed description of the mining cycle for each cutting technique, including the illustration of productive and non-productive cycle times, will be followed by a brief presentation of the performed production capacity calculation and a summary of the technical restrictions of each system. Standardised equipment classes for different seam heights are defined, after the most suitable and most productive mining equipment for each class are se-lected. Besides the technical parameters of the shearer loader and the AFC, the length of the long-wall face and the specific cutting energy of the coal are the main variables for each height class in the model. As a result of the capacity calculations, the different shearer cutting methods can be graphically compared in a standardised way showing the productivity of each method. Due to the general char-acter of the model, potential optimisations (resulting from changes in the cutting cycle and the benefits in terms of higher productivity of the mining operation) can be derived.
3 State-of-the-art of shearer loader cutting sequences
The question “Why are different cutting sequences applied in longwall mining?” has to be an-swered, before discussing the significant characteristics in terms of operational procedures. The major constraints and reasons for or against a special cutting method are the seam height and hard-ness of the coal, the geotechnical parameters of the coal seam and the geological setting of the mine influencing the caving properties as well as the subsidence and especially the length of the longwall face. For each mining environment the application of either sequence results in different production rates and consequently advance rates of the face. The coal flow onto the AFC is another point that varies like the loads on the shearer loader, especially the ranging arms and the stresses and the wear on the picks. A thorough analysis is necessary to choose the best-suited mining cycle; therefore, general solutions do not guarantee optimal efficiency and productivity.
A categorization of shearer loader cutting sequences is realised by four major parameters . Firstly, one can separate between mining methods, which mine coal in two directions – meaning from the head to the tailgate and on the return run as well – or in one direction only. Secondly, the way the mining sequence deals with the situation at the face ends, to advance face line after extract-ing the equivalent of a cutting web, is a characteristic parameter for each separate method. The nec-essary travel distance while sumping varies between the sequences, as does the time needed to per-form this task, too. Another aspect defining the sequences is the proportion of the web cutting coal per run. Whereas traditionally the full web was used, the introduction of modern AFC and roof sup-port automation control systems allows for efficient operations using half web methods. The forth parameter identifying state of the art shearer loader cutting sequences is the opening created per run. Other than the partial or half-opening method like those used in Matla’s “Opti-Cycle”, the cutting height is equal to the complete seam height including partings and soft hanging or footwall material.
Bi-directional cutting sequence
The bi-directional cutting sequence, depicted in Figure 1a, is characterised by two sumping opera-tions at the face ends in a complete cycle, which is accomplished during both the forward and return trip. The whole longwall face advances each complete cycle at the equivalent of two web distances by the completion of each cycle. The leading drum of the shearer cuts the upper part of the seam while the rear drum cuts the bottom coal and cleans the floor coal. The main disadvantages of this cutting method are thought to be the unproductive time resulting from the face end activities and the complex operation. Therefore, the trend in recent years was to increase face length to reduce the relative impact of sumping in favour of longer production time.
Uni-directional cutting sequence
In contrast to the bi-directional method, the shearer loader cuts the coal in one single direction when in uni-directional mode. On the return trip, the floor coal is loaded and the floor itself cleaned. The shearer haulage speeds on the return trips are restricted only by the operators’ movement through the longwall face, or the haulage motors in a fully automated operation. The sumping procedure starts in near the head gate, as shown in Figure 1b. The low machine utilisation because of cutting just one web per cycle is the main disadvantage of the uni-directional cutting sequence. Besides the coal flow can be quite irregular depending on the position of the shearer in the cycle.
Half web cutting sequence
第15頁(yè)
中國(guó)礦業(yè)大學(xué)2005屆本科生畢業(yè)設(shè)計(jì)
The main benefit of half web cutting sequences is the reduction of unproductive times in the mining cycle, which results in high machine utilisation. This is achieved by cutting only a half web in mid face with bi-directional gate sequences as shown in Figure 2a. The full web is mined at the face ends, with lower speeds allowing faster shearer operation in both directions in mid seam. Beside the realisation of higher haulage speeds, the coal flow on the AFC is more balanced for shearer loader trips in both directions.
Half-/partial-opening cutting sequence
The advantage of the half- or, more precisely, partial- opening cutting sequence is the fact that the face is extracted in two passes. Figure 2b shows that the upper and middle part of the seam is cut during the pass towards the tailgate. Whereas the last part of this trip for the equivalent of a ma-chine length the leading drum is raised to cut the roof to allow the roof support to be advanced. On the return trip the bottom coal is mined with the advantage of a free face and a smaller proportion of the leading drum cutting coal; consequently leading to less restrictions of the haulage speed due to the specific cutting energy of the material. The shearer sumps in mid seam near the head gate to the full web without invoking unproductive cycle time. Like for the trip the tailgate the leading drum has to be lowered a machine length ahead of the main gate.
4 Production capacity calculations
A theoretical comparison of the productivity between different mining methods in general, or in this case between different shearer loader cutting cycles, is always based on numerous assumptions and technical and geological restrictions. As a result, this production capacity calculation does not claim to offer exact results, although it does indicate productivity trends and certain parameters for each analysed method.
The model works with so-called height classes varying the seam thicknesses between 2m and 5m in steps of 50cm. Equipment is assigned to each class, having been selected by looking at the best-suited technical properties available on the market [4]. Apart from the defined equipment, it is assumed that the seam is flat and no undulations or geological faults occur. In the model, the ventilation and the roof support system represent no restrictions to the production. Since the aim of this model is to show ways to further increases in longwall productivity, the calculation is based on a fully automated system with no manual operators required at the face. The haulage speed of the shearer is therefore only restricted by the AFC capacity, the cutting motors and the haulage motors respectively.
The variable parameters in this comparison of the four cutting sequences are, (besides seam thick-ness) the specific cutting energy of the coal to be cut and the length of the longwall face. The former varying between 0.2 and 0.4kWh/m3, the latter between 100m and 400m in 50m intervals. The 100m shortwalls were deliberately selected, since they are coming more into focus for various reasons. Geotechnical aspects, like e.g. the caving ability of the hanging wall and faults, restrict long-wall panels in many places to maximum face lengths of 150m or less, like in South Africa and Great Britain. For this reason, a detailed analysis of the potential of such longwalls is deemed appropriate.
5 Conclusions
In recent years much effort has been put into the optimisation of longwall operations to increase productivity and efficiency. In many cases the emphasis of these improvements was mainly focused on the equipment, e.g. increased motor power or larger dimensions of AFC’s. The organisational aspect has sometimes been neglected or did not rank as high on the agenda as other topics. In this paper, it has been demonstrated that the selected mining method has a significant impact on the achievable productivity.
In a theoretical model four cutting sequences have been compared to each other while varying seam thickness, face length and coal properties in terms of specific cutting energy.
For each seam or height class a defined set of equipment was used with consistent restraints. Though each mine is unique, some general conclusions can be drawn analysing the capacity model. Under the restrictions of the model the half web cutting sequence offers the highest output of all analysed methods fol-lowed by the half-opening mode. Depending on the face length, the bi-directional cutting method has advantages compared to the uni-directional sequence in terms of higher productivity.
中文譯文
高效生產(chǎn) — 一個(gè)關(guān)于采煤機(jī)截割的次序的問(wèn)題
1 摘要
目前, 地面下長(zhǎng)壁采煤法致力于增加安裝在采煤機(jī)和甲板輸送機(jī)的電機(jī)功率, 以及更先進(jìn)的支架控制系統(tǒng)和增加工作面長(zhǎng)度,以達(dá)到減少費(fèi)用和取得較高的生產(chǎn)效率的目的。這種努力已經(jīng)造成較高的開(kāi)支和先前未見(jiàn)過(guò)的設(shè)備費(fèi)用增長(zhǎng)速度?，F(xiàn)在趨向于 "更大和更好" 的儀器和裝備，然而這種趨勢(shì)在技術(shù)上和費(fèi)用上的可行性已經(jīng)達(dá)到極限。為了要實(shí)現(xiàn)進(jìn)一步促進(jìn)生產(chǎn)力的增加，合理、有機(jī)地規(guī)范長(zhǎng)臂采煤法的工序應(yīng)該是解決提高生產(chǎn)效率問(wèn)題的唯一的合理答案。在本文中論述了通過(guò)合理安排采煤機(jī)的截割次序以實(shí)現(xiàn)提高采煤工作效率。
2 簡(jiǎn)介
傳統(tǒng)上，在地面下長(zhǎng)壁采煤法操作方面，采煤機(jī)挖掘過(guò)程中，使用以下截割次序之一:反方向的或雙方向的循環(huán)。除了這兩種主要的方法，交替循環(huán)采煤也已經(jīng)應(yīng)用在地下的硬煤層開(kāi)采中，它被成功地推廣在全世界的挖掘過(guò)程中。就半邊切斷循環(huán)舉例來(lái)說(shuō)，在科羅拉多,美國(guó)在二十里煤礦利用，而且 Matla's 的南非短巷道操作的開(kāi)采也在這被應(yīng)用。 其他類似的采掘已經(jīng)通過(guò)驗(yàn)證改進(jìn)截割次序能提高開(kāi)采產(chǎn)量,舉例來(lái)說(shuō)，它大約能夠在產(chǎn)量上增加40%的。
然而提到應(yīng)用在采煤上根據(jù)特殊情況而改變切割的方法,–用煤層高度和設(shè)備的使用來(lái)舉例說(shuō)明,論文系統(tǒng)地論述通過(guò)從不同的角度采取不同的方法。詳細(xì)描述了采礦的每種切割方法, 包括能生產(chǎn)的和不能生產(chǎn)的循環(huán),以下將會(huì)給出一個(gè)簡(jiǎn)短的關(guān)于采煤機(jī)生產(chǎn)能力的計(jì)算和每個(gè)系統(tǒng)在技術(shù)上的受到的約束的概要說(shuō)明。根據(jù)煤層的厚度采用不同標(biāo)準(zhǔn)的設(shè)備和合適的裝置 。此外采煤機(jī)和甲板輸送機(jī)，工作面的長(zhǎng)度和特定采煤機(jī)截割方式等技術(shù)參數(shù)在本模型中根據(jù)不同的煤層厚度而改變。
根據(jù)采煤的產(chǎn)量，不同采煤機(jī)截割的方法可以通過(guò)一個(gè)標(biāo)準(zhǔn)化方法繪制產(chǎn)量圖來(lái)反映不同截割方法的優(yōu)劣。 根據(jù)模型的特征,最優(yōu)的結(jié)果 ( 通過(guò)改變截割方式而得到的不同的采煤產(chǎn)量)就能獲得。
3 采煤截割次序的技術(shù)說(shuō)明
"為什么長(zhǎng)壁采煤法應(yīng)用的不同切割次序?"這個(gè)問(wèn)題是必須回答的,在以討論操作工序的主要規(guī)則之前，切割方法主要受到煤層的厚度和煤層硬度等因素的限制，就像煤層的物理參數(shù)和礦的地質(zhì)學(xué)條件影響煤的崩落能力一樣，同樣也會(huì)影響長(zhǎng)壁采煤法工作面的煤層塌方。對(duì)于不同的地質(zhì)條件，不同的截割次序都會(huì)得到不同的生產(chǎn)效率和不同質(zhì)量的工作面。 煤送入甲板輸送機(jī)之上正如采煤機(jī)截割，是采煤中的另外一個(gè)問(wèn)題,尤其是在截齒上受到的屈服應(yīng)力和疲勞應(yīng)力。 一個(gè)對(duì)于選擇最適合的截割次序的全面分析是必要的-適合采礦替換;因?yàn)?，一般性的解答是不能保證最佳的效率和產(chǎn)量。
對(duì)于一個(gè)采煤機(jī)截割次序的分類是通過(guò)四個(gè)主要的參數(shù)來(lái)規(guī)定的.第一，能在采礦方法之間分開(kāi),向礦井的兩個(gè)方向即從頭到尾。第二，根據(jù)截割次序，在到達(dá)工作面尾部, 預(yù)先在選取一個(gè)等價(jià)的線切斷網(wǎng),是區(qū)分截割方法的一個(gè)獨(dú)立的參數(shù)。必須有一定的距離空間以改變截割次序, 因?yàn)樽鲞@些需要一定的時(shí)間。 定義截割次序的另外一個(gè)方面是網(wǎng)狀斷煤的軌跡。 然而傳統(tǒng)地完整的使用, 現(xiàn)代的甲板輸送機(jī)和液壓支架系統(tǒng)允許使用有效率的一半網(wǎng)方法操作。區(qū)分截割工藝的以前那些參數(shù)就可以把不同的截割方式區(qū)分。除了部份或半開(kāi)口像被用在Matla的循環(huán)截割中的那些一樣的方法,切斷高度分別包括柔軟懸吊裝置和采煤機(jī)的高度，它和煤層厚度相等。
雙方向的截割次序
在圖1中被描述的雙方向的截割次序, 是表示工作面二點(diǎn)之間的特點(diǎn)，在一個(gè)完全的截割操作周期中, 是在兩者的向前和返回期間是完成的。整個(gè)長(zhǎng)壁采煤法每個(gè)周期的完成等價(jià)于在網(wǎng)狀截割軌跡的一個(gè)巡回。滾筒的前端面截割煤層的頂部而滾筒的后端面截割煤層的下部，同時(shí)起到清除落煤的作用。這個(gè)切割的方法主要的缺點(diǎn)主要表現(xiàn)在截割時(shí)間和操作比較復(fù)雜。 因此，趨勢(shì)近幾年來(lái)要增加工作面的長(zhǎng)度以減少挖掘過(guò)程中的沖擊載荷和延長(zhǎng)截齒的壽命。
單方向的截割次序
與雙方向的方法相反,在單向模型里截割采煤機(jī)截割是朝一個(gè)方向進(jìn)行的。 在回返行程中，地板煤是被采煤機(jī)底板它本身清理。截割運(yùn)動(dòng)在往返時(shí)被在工作面限制了操作運(yùn)動(dòng)推進(jìn)的速度。截割操作在工作面的開(kāi)頭部位,如圖1 b所示。因?yàn)榍懈顒?dòng)作只能是一個(gè)方向循環(huán)而使截割的工作效率低，它是單向截割次序的主要缺點(diǎn)。此外煤流可能是相當(dāng)不規(guī)則，它依賴于采煤機(jī)在截割周期中的位置。
半滾筒截割次序
半滾筒截割的主要優(yōu)點(diǎn)是它減少采煤機(jī)在截割過(guò)程中的無(wú)效截割時(shí)間,造成高機(jī)器利用。如圖 2 所顯示的半滾筒截割次序處于工作面中間位置時(shí)，它與雙方向截割次序具有一致性。完整的滾筒在截割結(jié)束時(shí),藉由更快速地允許的較低速度在煤層的中間部位向兩個(gè)方向操作。除了實(shí)現(xiàn)較高的牽引速度，在甲板輸送機(jī)被的采煤機(jī)雙向循環(huán)的煤流而平衡。
半開(kāi)口切割次序
這種方法的優(yōu)點(diǎn)更突出，它實(shí)際上是在二個(gè)方法中的提高和改進(jìn)。如圖2 b所示煤層的上端面和中間部分在向它的后端面時(shí)被截割。在回程底部的煤與自由的面和工作面的較小比例的來(lái)切斷煤層來(lái)一起截割；結(jié)果其牽引速度由于受到材料的切割能特性而限制。滾筒截割在煤層的中間部位不會(huì)產(chǎn)生無(wú)效的截割時(shí)間。類似的回程后門(mén)工作面必須在進(jìn)入主工作面之前減小機(jī)身長(zhǎng)度。
4 生產(chǎn)力計(jì)算
不同的采礦方法之間的生產(chǎn)力在理論上的做一個(gè)大體的比較, 因?yàn)樵谶@情況通過(guò)在不同的之間采煤機(jī)的截割周期,總是存在很多假定和技術(shù)上的以及地質(zhì)學(xué)的限制為基礎(chǔ)。因而，不能提供精確的結(jié)果,但是它為每個(gè)截割方法的分析確實(shí)提供了生產(chǎn)力的高低趨勢(shì)和某些參數(shù)。
該模型實(shí)用于煤層厚度在2 m 和 5 m 之間以50cm為一個(gè)等級(jí)的被稱之為厚煤層的煤礦類型,根據(jù)不同的等級(jí)選擇不同的設(shè)備，可以在市場(chǎng)上選擇最適合該等級(jí)開(kāi)采的設(shè)備。除了規(guī)范儀器之外，它假設(shè)煤層是平坦的且沒(méi)有波動(dòng)和地質(zhì)上的缺陷。在模型中，通風(fēng)和頂層支持系統(tǒng)不對(duì)生產(chǎn)超出限制。 既然這一個(gè)模型的目標(biāo)要實(shí)現(xiàn)進(jìn)一步的增加生產(chǎn)力，該計(jì)算是基于在沒(méi)有人工的操作干預(yù)的情況下一個(gè)完全自動(dòng)化的系統(tǒng)操作的工作面。制約牽引速度的唯一因素是甲板輸送機(jī),切割電動(dòng)機(jī)和牽引電動(dòng)機(jī)相互獨(dú)立。
通過(guò)比較四種截割次序的可變參數(shù) (除了煤層厚度) 煤截割的能耗和長(zhǎng)壁采煤法的工作面的長(zhǎng)度被降低。前者在0.2 到0.4，后者在100 m 和 400 m 之間每間隔50 m，因?yàn)樗鼈兪艿蕉喾矫娴囊蛩赜绊憽?在地理方面, 像舉例來(lái)說(shuō)墻壁崩落能力和缺陷,它限制煤層最大工作面長(zhǎng)度達(dá)到150 m, 像在南非和英國(guó)。 因?yàn)檫@一個(gè)原因,如此一項(xiàng)詳細(xì)長(zhǎng)壁采煤發(fā)的潛在可行性分析被認(rèn)識(shí)合理的。
煤層厚度
采煤機(jī)
截割電機(jī)
滾筒
直徑
SL
清理區(qū)
甲板輸送機(jī)
寬
輸送區(qū)
電動(dòng)機(jī)
2.0m
SL 300
2×480kW
1500mm
0.40
1332mm
0.67
3×800kW
2.5m
SL 300
2×480kW
1600mm
0.60
1332mm
0.67
3×800kW
3.0m
SL 300/
SL 500
2×480kW
2×750kW
1600mm
0.75
1332mm
0.67
3×800kW
3.5m
SL 300
2×750kW
2000mm
0.75
1332mm
0.67
3×1000kW
4.0m
SL 300
2×750kW
23mm
1.00
1532mm
0.87
3×1000kW
4.5m
SL 300
2×750kW
200mm
1.00
1532mm
0.87
3×1000kW
5.0m
SL 300
2×750kW
2700mm
1.00
1532mm
0.87
3×1000kW
5 總結(jié)
近幾年來(lái)，很多工作都是致力于長(zhǎng)壁采煤法的最優(yōu)化以增加到生產(chǎn)力和效率的目的。在許多情況，他們過(guò)于強(qiáng)調(diào)把重心集中在設(shè)備,舉例來(lái)說(shuō) 增加甲板輸送機(jī)的電動(dòng)機(jī)功率和增大其尺寸。而某些積極的方面有時(shí)被在不同程度上被忽略，它們沒(méi)有被提升到一個(gè)比較重要的日程。 在論文中，通過(guò)選擇不同的截割次序的采礦方法在生產(chǎn)力上所取得的成功產(chǎn)生深遠(yuǎn)影響。
當(dāng)煤層厚度、工作面長(zhǎng)度、煤層的性質(zhì)以及相關(guān)的截割能耗改變時(shí) ,四中截割模式在一個(gè)理論上可以進(jìn)行相互比較。對(duì)于每種煤層和其厚度等級(jí)的限制而選擇響應(yīng)的設(shè)備。雖然每種截割方式不同,但通過(guò)分析該模型可以得到一般性的結(jié)論。根據(jù)模型的約束條件，半滾筒截割的產(chǎn)量最高；在相同的工作面長(zhǎng)度的情況下,雙方向的截割方法比單方向的截割方法生產(chǎn)率高。