外文翻译--现有开采方法在矿井深部开采中应用的评估

中文2975字
英文原文
PROSPECTS ESTIMATION OF KNOWN SYSTEMS APPLICATION FOR COAL SEAMS MINING AT GREAT DERTH
Prof.w.p.Zubov
Leningrad Mining Institute
Abstract：Estimation of present and future situation in technological schemes on coal mining at great depth applying highly productive mechanized complexes is presented here, Stis shown that the decrease both in operation concentration and the share of pillar mining at deep mines is connected with increasing difficulties in development working support behind the face as well as prevention of roof caving in face area.
Introduction：
Underground coal mining efficiency depends at Iarge extent on technical economic indices of deep mines, the level of their development being steadily increased. In transition to deeper levels specific expenditures increase parallel with the deterioration of geological conditions in coal seams mining. At mines of Donetsk basin where seams are mined at a depth of 500m ad more, the depth increase for every 100m results in production cost to 3-4%,here labour productivity of miners decreases in 6-8%[1].
One of the main effective ways to neutralize negative depth influence on under-round coal mining efficiency is to increase average daily face output on the basis of using complex mechanization in stopping.
At non-gassy mines the application of long pillar mining leads to face output in 1.2-1.65 times compared to average daily face output in longwall combined methods.
Even more effective appeared to be long pillar mining in stopping under condition characterized by increased gas emission in goaf.
In gassy mines the face output is determined taking into account the requirement of methane dilution up to permissible concentration, with methane emitting into ventilation current. In long wall and combined methods the intake air should enter the face along one of the development workings and the return air runs along the other development working. Maximum intake air quantity to the stope depends on both air current veloclty, regulated by safe security rules in working area and cross section area of the face which is free for air current passage. The factors mentioned above
being of non-regulated nature, if becomes practically impossible to increase the quantity of intake air to he panel. According to the reasons discussed at mines with increased methane emission the actual average daily face output in longwall and combined methods in 3-5 times less than the face output level which may be reached using in full modern highly productive methods of mining.
The application of long pillar mining permits prior to stopping to carry on some measures for seam degasification and use more effective schemes of panel ventilation.
Thus in applying both long pillar mining in the variant “face-sub-panel” and in shuttle scheme of panel ventilation relatively high face output (1000-1500t/day)may be reached at mines with relative gas emission up to 15m3/t, as well as at mines with higher gas emission when methane does not emit from the goaf.
In estimating the prospects of long pillar and longwall mining as the space and plan basis for technological schemes in stopping operations at great depths, it is also necessary to evaluate the following factors. With the increase of coal seams depth, the methane content both in workings and in seams changes according to hyperbolic curve approaching to some limited value. The stronger influence of depth is more evident in gassy zones associated with developed areas of coal-bearing deposits containing seams composed of coal marks, high collector properties of coal-earing measures and, hence ,the propogatlon of gas zone emission to greater depth are responsible for this. The mentioned regularity of methane-bearing capacity change in workings of Donetsk basin is also notieed at mines of Donetsk-Makeevsk, krasnoarmelsk, Almazno-Marjevsk,V oroshllov-gradsk and krasnodonsk geological and industrial regions.
In the regions where antracite groups 11A-12A occur lower than the zones of gas emission, natural gas content increases at first up to maximum and then decreases sharply in values typical for zones of gas ecmission [2]. Such character of natural gas content change marked for measures C of Torezsk-Snezhnyansk region and measures C of Bokovo-Chrustalsk geological-industrial region may be explained by the increase of metmorphism grade of antracite seams with the depth increase.
Practically speaking in donetsk basin methane content of seams is not traced onlyin its southeastern parts, where the seams up to a bepth of 1600 m are represented by high metamorntosed antracites. Therefore, in the nearest future gas factor influence on economic efficiency of underground coal mining will be increasing in the USSR.Taking into account good results achieved by known ways of preliminary seams gasitication, it should be assumed that the most negative influence of operation effioncy with wide use of long pillar mining will be in mines where gas emission in more can 15 m3 per ton of daily output. Donetsk basin illustrates the tendency of this factor with depth increase, there the number of highly categorized mines in 1940 was
17%, in 1970-45%, in 1980-60%, in the late 1987-68.8%, the average depth of coping during the period studied increased from 198 to 659.
The fact that gas emission from the developed area increases panel gas balance depth deserves special attention in estimating some prospects of longwall. Thus, in Donetsk basin a coal seam up to 600 m depth becomes the main source of gas emitting into stopes and development workings, methane emission from the coal seam is 40-50%and in some cases up to 20% of total gas emission volume in transltion of mining operations to a depth of 700-1000m. Besides at deep levels the preliminary degasification efficiency of measures on seam degasification by common methods is not more than 15-30% at great depths. However, the required decrease of gas emission in workings should be not less than 60-70%, here the restrictions on gas factors being lifted.
Thus gas emission from the developed area becomes the main factor determining maximum face output in seam mining at great depths. Under these conditions to solve the problem of panels ventilation only by seam degasification measures seems impossible.
In highly categorized mines with gas emission not more than 40% during stopping some restricting on ventilation can be overcome only be applying direct scheme of panel ventilation with return air freshing in goaf. But this scheme of ventilation is practically realized only in pillar mining.
The facts mentioned above indicate that the increased application of pillar mining combined with direct ventilation schemes should be considered as priomising and economically proved. It perfects deep mining when highly productive mechanized mechanized complexes are used.
Though in Donetsk mines the problem concerning the average daily face output increase is acute, the share of pillar mining comprises not more than 43%, including about 10% of pillar mining with direct panel ventilation. Moreover, with depth there is a strong tendency of decreasing the number of faces developed by pillar mining. Thus in “Makeevugol” m ines the share of pillar mining decreased from 60 to 35% during the period of 1975-1985. The average depth of mining during this period increased in 276m, being 860m in 1985.
As a whole in Donetsk basin the share of pillar mining in mines extracting seams at depths up to 600m is 48.2%, at depths of 600-1000m it is 40.2% and at depths more than 1000m it is not more than 19%.Now at deep levels long wall and combined methods of mining in the so-called “single face” variety are widely used.
Long wall and combined (in the shape of) methods prevail in deep mines of FRG. In the late 1985 their share in the number of faces was more than 65%, as to their share in the overall mining of commercial coal it was 62.2%[3].
Taking into account that at large depths seams are mined in new or reconstructed mines the share of pillar mining decreases with depth. Thus, this fact reflects the tendency to change the technological schemes of mines with transition of mining to deeper levels. This tendency is in contradiction with progressive directions of underground coal mining technology preventing negative rock pressure manifestation.
The investigations carried out showed that the decrease of pillar methods in deep mines is caused mainly by the following reasons. When mining at deeper levels there appeared more difficulties to maintain district development working at deeper seams at depths of 800-1200m expenditures on sub-level maintenance in pillar mining are 1.5-2.5 times more than these in longwall mining. In pillar mining reliable means of safety and support providing stability in development workings behind the longwall face are absent. And in a number of deep-mines this fact became the main reason to refuse from previously accepted in the projects of these mines pillar mining with return air freshing in coal. With depth during pillar mining the solution of problems connected with the prevention of roof caving in face area becomes more difficult than in longwall mining. At deep levels in pillar mining as a result of caving the idle time in face is 20-35% more than that of in longwall mining, Such a differene in idle time as to the factor considered is mainly explained by different roof control in face ends adjacent to development workings. In pillar mining and non-pillar measures of development workings protection in face ends with total length not more than 20-25% that of the length the caving comprises up to 45% of whole roof caving. In longwall mining this magnitude does not exceed 5-7%.
In non-pillar seam mining the use of longwall systems produces means to increase the number of faces adjacent to one inclination and thus to reduce the length of main development workings that should be supported, markedly decreasing the application of pillar mining in deep Donetsk mines. Therefore, in panel mine development at longwall mining in the variety “face-level” it becomes possible to develop two faces as well as to prepare simultaneously another two faces within the two-sided panel. In pillar mining this becomes possible only in driving additional flanking workings.
SUMMARY
1.At great depth of mining characterized by great gas emission in goaf it becomes possible to increase greatly daily average face output only by using pillar mining. This system allows to use direct panel ventilation schemes with return air freshing in goaf.
2.The decrease of pillar mining with depth increase is mainly connected with the absence of supports and means of safety at miner’s disposal that should provide workings stability behind the face during pillar recovery when swelling
rocks occur in the seam bottom, as well as the ways of rock pressure control that eliminate rock caving in face ends.
1.Grinko N.K. Some problems in deep mines. Coal, 1989,N 9,p.p.21-2
2.
2.Brizanev A.M. Methane distribution regularity in Donetsk Basin. M.Ugol,iss. 6,1986,p, 3
3.
3.Clas F.Faift P.The state of panels in FRG coal industry by l985. Glückauf, 1985,N24,P.P.19-2
4.
中文译文
现有开采方法在矿井深部开采中应用的评估
W．P．Zubov教授
（苏）列宁格勒矿业学院
摘要：本文介绍了用综合机械化开采矿井深部煤层时当前和未来技术状况的评估。

可以看出，降低集中开采程度和减少柱式开采法所占的比例，将增加工作面后方采准巷道支护的困难并使工作面顶板陷落的防止更加困难。

概述：
煤矿地下开采的效益在很大程度上取决于矿井深部煤层开采的技术经济指标，矿井开采的深度正在逐步增大。

在向较深水平过渡时，随着煤层开采的地质条件的恶化，所需的额外的资金也增加了。

在顿涅茨克煤田的很多矿井中，煤层埋藏深度已超过500 m，开采深度每增加100 m，生产费用就增加3～4%，工人的劳动生产率就下降6～8%。

抵消深度对煤矿地下开采效益影响的主要有效方法之一是在回采工作面使用综合机械化装备的基础上提高工作面平均日产量。

在无瓦斯矿井，应用长壁开采法导致工作面产量较长壁联合开采法增长了1.2～1.65倍。

甚至在采空区瓦斯涌出量增加的条件下，长壁开采法也显得很有效。

在瓦斯矿井中，工作面产量取决于甲烷稀释到允许的浓度并排放到风流中去这一通风方面的要求。

采用长壁联合开采法时，入风流应沿一条采准巷道进入工作面，回风流则沿另一条巷道排出。

进入工作面的最大风量取决于按安全规程规定的采区风流风速以及现流自由流过工作面的横断面面积。

由于风速和断面的限制，实际上不大可能增加进入盘区的入风量。

按上述理由，在甲烷涌出量增加的矿井中，用长壁联合开采法的工作面实际平均日产量较综合机械化开采法低3~5倍。

应用长壁开采法允许开采前采取一些措施排放煤层瓦斯并采用更有效的盘区通风方式。

这样，当矿井中相对瓦斯涌出量达到15 m3/t，或当采空区中尚无甲烷涌出而矿井中瓦斯当量较高时，无论是在不同的“工作面——子盘区”系统中还是在往复式盘区通风方式中，应用长壁开采法都可能取得相对较高的工作面产量（1000~1500 t/d）。

评估长壁和长壁开采法矿井深部回采工序及其空间和在计划基础上的技术方案时，下面的因素值得考虑。

随煤层深度的增加，甲烷在采区和煤层中的含量都呈双曲线变化并达到某一限定值。

在与已开发的煤层走向沉积地区有联系的瓦斯地带，较强烈的深度影响非常明显。

煤层走向范围高度集中以及由此引起的瓦
斯排放向较深的地下传播，是上述现象形成的原因。

这种甲烷承载能力变化规律在顿涅茨吉克煤田开采下列矿井中也注意到了，即马克维斯克，凯瑞莫斯克，奥马维斯克和维瑞斯劳瑞斯克矿井以及凯瑞德斯克地质工业区。

无烟煤组11A～12A地带的瓦斯涌出量低于正常地区，在那里，自然瓦斯含量一开始就上升并达到极值，然后急剧下降到典型的瓦斯涌出地区的数值[2]。

这种自然瓦斯含量变化的特征已在Torezsk-Rovenetsky 地区C32煤层中测出，在Bokovo-Chrustalsk地质工业区的C52煤层中也已测出这种特征可以用随着无烟煤埋藏深度的增加其变质程度也随之增加来进行解释。

实际上，在顿茨克煤田煤层中甲烷含量仅仅在煤田东南部分未被测到，在那时，煤层深达1600 m，为高度变质的无烟煤。

因此，苏联在近期煤矿地下开采中，瓦斯这一因素在经济上的影响将会增大。

考虑到现有的原始煤层排放瓦斯的方法取得的良好效果，可以假定，矿井中广泛采用长壁开采时，对于开采效益最大的负影响发生在瓦斯涌出量超过15 m3/t。

日的矿井中。

顿茨克煤田列出了这一因素随深度增加而变化的趋势，1940年，高与瓦斯类型矿井数量占17%，1970年为45%，1980年为60%1987年后期占68.8%。

在此期间平均开采深度从198 m增至659 m。

开采地区的瓦斯涌出量增加了盘区瓦斯深度变化的平衡关系，在评价长壁开采的某些方面时，这一事实应引起特别的注意。

在顿涅茨克煤田，某一煤层埋藏至600 m深时，便成为涌入工作面及开采区的瓦斯的主要来源。

从该煤层中排放的甲烷含量为40～50%，在某些情况下可升至瓦斯总涌出量的20%，此时开采深度为700～1000 m。

除受深度影响外，初期瓦斯排放高效率也因煤层瓦斯渗透性的降低而下降。

事实上，用常规方法测得深部煤层瓦斯排放的实际效率不超过15～30%。

而要求降低开采时的瓦斯涌出量的数值不应低于60～70%，此时瓦斯因素的限制条件更加严格了。

因此，开采地带的瓦斯涌出成为限制矿井深部开采时工作面最高产量的主要因素。

在这种条件下，仅采用排放煤层瓦斯这一措施来解决盘区的通风问题似乎是不可能的。

在瓦斯涌出量不超过40%的高瓦斯矿井中，可以采用直接使回风流流入采空区的盘区通风方式来解决开采期间一些通风限制问题。

但这种方式实际上只能在柱式开采法中使用。

上述事实指出，增加柱式开采法的应用与直接通风方式有关，这种应用，对条件是否允许要进行考虑并从经济上加以验证。

当采用综合机械化开采时，深部开采会更完善。

虽然在顿茨涅克煤田的许多矿井中增加平均日产量这一问题十分尖锐，但是柱式开采法所占的比例不超过43%，这还包括约占10%的用直接盘区通风方式的柱式开采法在内。

再者，还存在一种强烈的趋势，即要求减少深部开采时使用柱式开采法的工作面数量。

因而，在Maxeevugol许多矿井中，从1975至1985年期间，柱式开采的比例由60%降至35%。

同期平均开采深度增加了276 m，即
达到1985年的860 m。

在整个顿涅茨克煤田，用柱式开采法开采的煤层所占的比例，当深度600时为48.2%，深度600～000 m时为40.2%，深度超过1000 m时不超过19%。

目前，长壁联合开采法在所谓的多种单工作面中得到广泛应用。

长壁联合开采法在西德深井中普遍采用。

1985年后期，采用这种方法的工作面所占的比例超过65%。

就商业用煤所使用的全部开采法而言，长壁联合开采法占的比例为62.2%。

考虑到在新井或老井改造的矿井中，深部用柱式开采法的比例随深度下降这一事实，反映了使用过渡的开采法改变矿井的技术体系以过渡到较深水平这一趋势。

这种趋势与地下开采技术改进的发展方向是矛盾的。

实际生产中矿工们常采用一些措施用以预防岩石跨落。

调查表明，深井中柱式开采法应用减少的主要原因是，当在较深水平开采时，用柱式开采法维护采准巷道地段要比用长壁联合法困难。

因此，在深度为800～1200 m的矿井中开拓煤层时用于分水平的维护费用，柱式开采法为长壁开采法的1.5～2.5倍。

在柱式开采法中缺乏可靠安全的支护手段，已保证在长壁工作面后方的采准巷道的稳定性。

在一定数量的深井中，这一点成为从前接受回风流可流入采空区的柱式开采法现在又拒绝这种方法的主要原因。

随着开采深度的增加，柱式开采法需要解决防止工作面顶板陷落问题，正是这一点柱式开采远比长壁式开采法困难。

用柱式开采深部水平时，由于顶板陷落使工作面的无效时间较长壁开采长20~35%。

这种无效时间的不同，可以用在临近巷道的工作面端部顶板控制的不同来加以解释。

用柱式开采法时，用以保护工作面端部的采准巷道非煤柱尺寸不应超过工作面长度的20~25%，巷道陷落高度可达整个顶板陷落的45%。

而在长壁开采法中此值不超过5~7%。

在非柱式煤层开采发中，使用长壁系统可以增加与邻近一侧倾斜方向的回采工作面数量。

以此减少需维护的主要采准巷道的长度，从而使柱式开采发在顿茨涅克深部矿井中的应用明显减少。

因而，在用长壁开采各种“工作面水平”的盘区矿井布置中，可以在同一盘区的两翼分别布置两个工作面。

而用柱式开采法则只有当掘进附加侧翼巷道时才有可能这样做。

结论
(1)在采空区涌出的瓦斯量大这一特点的矿井进行深部开采时，只有使用柱式开采才能大大提高工作面平均日产量。

柱式开采体系允许使用让回风流通过采空区的直接盘区通风方式。

(2)柱式开采法的应用随深度的增加而减少，这主要是由于这种方法缺乏对矿工们的工作场所提供必要的支护和安全手段，与控制工作面端部岩石冒落的矿压方法相类似，当底鼓发生时，这种手段能提高回收煤柱期间工作面后方巷道稳定性。