Ach. Min. Sci., ol. 6 (206), No 4, p. 967 977 Electonic vesion (in colo) of this pape is available: http://mining.achives.pl DOI 0.55/amsc-206-0064 RYSZARD SNOPKOWSKI*, ANETA NAPIERAJ*, MARTA SUKIENNIK* METHOD OF THE ASSESSMENT OF THE INFLUENCE OF LONGWALL EFFECTIE WORKING TIME ONTO OBTAINED MINING OUTPUT METODA OCENY WPŁYWU EFEKTYWNEGO CZASU PRACY W ŚCIANIE NA UZYSKIWANE WYDOBYCIE Method of the influence of assessment of longwall effective woking time onto obtained mining output, has been discussed in the pesent study. Mean flow ate of the winning steam being also consideed as diectional facto of linea function descibing elation between daily output and effective mining in the longwall face, has been detemined. Such elation pesented also gaphically in fom of the diagam detemines significance and influence of the effective woking time onto obtained mining output. This elation should be consideed as motivation in paticula fo supevisoy pesonnel, as it shows advantages esulting fom elongation of this time, as well as it shows possible loses of the daily output in a case, when the effective woking time in given longwall face was shotened. Keywods: longwall faces, poduction pocess, daily output, effective woking time, effectiveness of poduction pocess Teścią pacy jest metoda oceny wpływu efektywnego czasu pacy w ścianie na uzyskiwane wydobycie. Wyznaczane jest śednie natężenie stugi uobku, będące jednocześnie współczynnikiem kieunkowym funkcji liniowej, opisującej zależność wydobycia zmianowego od efektywnego czasu pacy w pzodku. W ten sposób wyznaczona zależność pezentowana także gaficznie w fomie wykesu zwaca uwagę na znaczenie i wpływ efektywnego czasu pacy na uzyskiwane wydobycie. Powinna działać motywacyjnie (w szczególności chodzi o pacowników dozou uchu), gdyż pokazuje kozyści wynikające ze zwiększenia długości tego czasu, ale także pokazuje możliwości stat w wydobyciu zmianowym, jeśliby efektywny czas pacy w danym pzodku ścianowym uległ skóceniu. Słowa kluczowe: pzodki ścianowe, poces podukcyjny, wydobycie zmianowe, efektywny czas pacy, efektywność pocesu podukcyjnego * AGH UNIERSITY OF SCIENCE AND TECHNOLOGY, FACULTY OF MINING AND GEOENGINEERING, AL. A. MICKIE- WICZA 30, 30-059 KRAKÓW, POLAND
968. Intoduction In Polish had coal mines mining woks ae conducted in longwall faces equipped with longwall systems. i.e. sets of machines suitably selected with espect to mining efficiency and thei mutual cowoking. Technical paametes of the longwall system ae so high that they don t distub obtaining high woking efficiency. i.e. highe poduction efficiency in longwalls (Snopkowski & Sukiennik, 202). So, what in actual conditions paticulaly stong influences the mining output being a baie of its incease? So called effective woking time (T e ) gives answe to this question. It is time in which poduction pocess can be ealized, i.e. time spent by the pesonnel in the longwall face, minus time lost in esult of bake-downs and woking beaks independent on technology used In the longwall face. Thus length of the effective woking time is influenced by the time of beak-downs and woking beaks not esulting fom the technology used and length of time spent by the pesonnel in the longwall face, what is dependent on the distance between the longwall face and pesonnel pit shaft (Snopkowski & Sukiennik, 203). Finally we can assume that incease of the effective woking time causes gowth of the obtained winning output in conditions occuing in evey longwall face. Howeve it is pactical question: what mining output gowth could be expected if effective time of the longwall face wokings was elongated? In ode to answe this question daily longwall output in function of effective woking time fo given conditions and technology used should be detemined. Elaboation and use of such chaacteistics in pactice could be motivational fo pesonnel paying attention to the meaning and influence of effective woking time onto obtained output. So such chaacteistics should be in disposal of supevisoy pesonnel of each longwall. Based on the above pemises, method of the assessment of the longwall effective wokings onto eceived mining output fo vaious mining technologies, has been developed and descibed in next chaptes of the pesent study. Pocedual scheme of the poposed method is shown in Fig.. Calculation of mean flow ate of the winning steam with espect to given technology used In the longwall face Calculation of the level of effecting woking time fo given longwall face Assessment of the influence of woking time onto obtained daily output fo given longwall face Fig.. Algoithm of the method of assessment of the woking time influence onto daily mining output fo given longwall face (Elaboated by the authos of the pesent study)
2. Mean flow ate of the winning steam fo vaious longwall sheae based mining technologies 969 Fo each technology applied in the longwall face we can detemine mean flow ate of the winning steam obtained duing poduction cycle, which is dependent on mining output fom this cycle, cycle duation and mode of the sheae cutting. Pocedue of calculation of the mean flow ate of winning steam fo technologies commonly used in longwall faces is descibed in the pesent study. It should be noted that only these technologies ae applied, so fa. Quite fequent ae solutions in which, fo example, place of the sheae slotting is diffeent than at the end of the longwall. Howeve, it should be undelined that pesented detailed analysis of the poduction cycle can also be used in such cases (Snopkowski, 2000). alue of the mean flow ate of the winning steam is used in futhe calculations of the influence of effective longwall woking time onto obtained mining output. Method of calculation of φ k mean flow ate of winning steam in technology of sheae-based unidiectional mining Scheme of the poduction cycle executed in technology of sheae-based unidiectional mining is shown in Fig. 2. etical axis eflects longwall length, wheeas hoizontal axis is scaled in time units. Sheae slotting is made at the end of the longwall in manne shown in the scheme. Fig. 2. Scheme of the poduction cycle fo technology of unidiectional sheae mining (Snopkowski & Napieaj, 202)
970 The scheme in question compises all activities and woks needed fo coal mining execution on the total longwall length at the depth of single web, dive units of the longwall conveyo wok in vetical system (no niches ae made). The following makings ae pesent on the diagam: L longwall length [m], T c duation of poduction cycle [min], t,t 2,...,t 8 times of execution of individual phases of the poduction cycle [min], d k sheae length [m], x,x 2,x 3 mutual distances of executed activities and wokings in scope of the system sheae suppot conveyo [m], x p distance between sheae stoppage place and longwall-oadway cossing [m]. Duation of the poduction cycle is a sum of ealization times of its phases (Snopkowski & Napieaj, 202), so: whee: T t t t t t t t t () c 2 3 4 5 6 7 8 t xp dk (2) z z advance ate of slotted sheae [m/min]. Time t 2 is a time of the dive unit elocation, beginning fom the moment of pillas descending up to the moment of thei expanding, afte shift of full web. sheae woking advance ate [m/min]. t3 xp dk (3) t4 xp dk (4) cz cz sheae advance ate (sheae advance ate duing sheae tack cleaning) [m/min] t5 Lxp dk (5) t x x x d (6) 6 2 3 cz x = d k + s [m], whee s distance between potable suppot and sheae [m], x 2 distance between potable conveyo and suppot [m], x 3 = d k + p [m], whee p minima distance between potable conveyo and sheae [m]. Time t 7 is a time of tuning station elocation detemined analogically as in case of time t 2. 8 2 3 cz k t Lx x x (7)
Thus duation of the poduction cycle fo technology of sheae-based mining pesented in scheme 2 (afte substitution into fomula ) has following fom: 97 Tc xp dk Lxp dk Ldkt2 t7 (8) z cz cz Mean flow ate of the winning steam in poduction cycle, executed in technology of unidiectional sheae-based technology φ k is detemined by fomula: Wc k (9) T c φ k mean flow ate of the winning steam in technology of unidiectional sheae-based technology [Mg/min] W c output fom poduction cycle [Mg/cycle] Wc whee: H longwall height [m], z sheae web [m], L longwall length [m], γ coal bulk density [Mg/m 3 ], ρ web facto [-]. H zl (0) Afte substitution into fomula (9), mean flow ate of the winning steam in technology of unidiectional sheae-based technology φ k is calculated fom fomula: k HzL xp dk Lxp dk Ldkt t z cz cz 2 7 () Calculation pocedue φ 2k mean flow ate of the winning steam in technology of two-diectional sheae-based mining Scheme of the poduction cycle executed in technology of two-diectional sheae-based mining is shown in Fig. 3. Longwall length is maked on vetical axis and hoizontal axis is scaled in time units. Sheae-based mining is ealized with full longwall height in both diections. Sheae slotting takes place at the longwall end in manne shown in the diagam. The scheme in question compises all activities and wokings needed fo the coal mining on whole longwall length with single web cutting depth, including longwall conveyo dive units, which ae opeated in pependicula system (no niches ae made). In the Fig. 3 used following designations: L longwall length [m], T c duation of the poduction cycle [min], t,t 2,...,t 6 times of execution of individual phases of poduction cycle [min], d k sheae length [m],
972 x,x 2,x 3 mutual distances of executed activities and wokings in scope of the system sheae suppot conveyo [m], x p distance between place of sheae standstill and longwall-oadway cossing [m]. Fig. 3. Scheme of the poduction cycle executed in technology of two-diectional sheae-based mining (Snopkowski R., Napieaj A., 202) Duation of the poduction cycle (executed in technology pesented in Fig. 3) is a sum of times of ealization of individual cycle phases, thus whee: cz sheae advance ate [m/min]. T t t t t t t (2) c 2 3 4 5 6 t xp dk (3) cz Time t 2 is a time of the dive unit elocation, beginn ing fom the moment of descending of pillas, up to the moment of thei expansion afte shifting with full web. sheae woking velocity [m/min]. t3 L xp (4) 4 2 3 z t x x x dk (5)
973 z pędkość kombajnu w takcie zawębiania [m/min], x = d k + s [m], s distance between elocated suppot and sheae [m], x 2 distance between elocated conveyo and suppot [m], x 3 = d k + p [m], p minimal distance between elocated conveyo and sheae [m]. Time t 5 is a time of tuning station elocation, beginning fom the moment of descending of pillas, up to the moment of thei expansion afte shifting with full web. t x x x dk (6) 6 2 3 Duation of poduction cycle executed in technology of sheae-based two-diectional mining (afte substitution to fomula 2), thus: T x d Lx x d pst t c p k p 2 k 2 5 cz z Mean flow ate of the winning steam obtained in technology of sheae-based two-diectional mining φ 2k (Snopkowski, 2005), (Snopkowski, 2009) is calculated fom fomula: c (7) Wc 2k (8) T φ 2k mean flow ate of the winning steam in technology of sheae-based two-diectional mining [Mg/min] W c poduction cycle output [Mg/cycle] Wc whee: H longwall height [m], z sheae web [m], L longwall length [m], γ coal bulk density [Mg/m 3 ], ρ web facto [-]. Afte substitutions: H zl (9) 2k H zl xp dk Lxp x dk pst t cz z 2 2 5 (20)
974 3. Assessment of the influence of the longwall effective woking time onto obtained mining output Output obtained duing poduction shift can be calculated fom the following fomulas. Fo sheae-based unidiectional mining technology: W T (2) zm e k Fo sheae-based two-diectional mining technology: W T (22) zm e 2k whee: W zm daily/pe shift output [Mg/shift], T e effective woking time fo single shift [min/shift], φ k, φ 2k mean flow ate of the winning steam (accoding to fomula o 20) [Mg/min]. Fig. 4. Daily mining output in function of mean flow ate of the winning steam and effective woking time (Elaboated by the autho of the pesent study) Diagam eflecting dependence of the daily output (z) on mean flow ate of the winning steam (y) and effective woking time (x) is shown in Fig. 4. Maximal values wee assumed at the level of theoetical tanspot efficiency of longwall conveyo (y), assuming also effective woking time (x) as 420 min.
975 In pactice, obtained values have consideably lowe level, howeve, mentioned diagam allows assessment of the of geneated in the longwall face mean flow ate of the winning steam and effective woking time onto obtained output, within boad scope of values (Snopkowski, 2002). Concete step in developed method (accoding to Fig. ) compises assessment of effective (eal) woking time fo conditions occuing in given longwall face. Data needed fo assessment of this time should be taken fom shift epots and opinion of supevisoy pesonnel. Such detemined effective (eal) woking time is maked with T e. Using detemined fo conditions occuing in given longwall face values of mean flow ate of winning steam (accoding to fomula o 20) and effective woking time T e level of the daily output W zm is calculated: fo unidiectional mining, o fo two-diectional mining. zm e * k W T (23) zm e * 2k W T (24) Thus paamete W zm can be consideed as the mining output level, which duing single woking shift can be obtained fom the longwall face at emaining constant (actual, eal) length of the effective woking time T e. In ode to detemine advantages o eventual loses in obtained output, diagam of daily output in function of effective woking time should be developed. Level of actual daily output W zm, obtained fo actual effective woking time T e is plotted on the diagam in question. Aeas of so called potential output ae maked on the diagam. Potential output is defined as such output level, which could be obtained in the longwall face, if length of the effective woking time exceeded actual value o was even shote. Pocedue of the diagam ceation is shown in calculation example illustating developed methodology, what is descibed in sub-chapte 3. of the pesent study. 3.. Example of the assessment of effective woking time influence onto obtained mining output Data used in this example ae elated with fully mechanized longwall face, in which technology of two-diectional mining technology was applied. Fo conditions occuing in this longwall face, mean flow ate of the winning steam was calculated accoding to the fomula (20): 2k H zl xp dk Lxp x dk pst t cz z 2 2 5 Data used in this fomula possessed the following values: longwall height (H) 3,4 [m], sheae web (z) 0,6 [m], longwall length (L) 260 [m], coal bulk density (γ),3 [Mg/m3], web facto (ρ),0 [-], maneuve sheae advance ate ( cz ) 24 [m/min], distance between sheae stoppage place and longwall oadway cossing (x p ) 25 [m], sheae length (d k ) 2 [m], woking sheae advance ate ( ) 0 [m/min], sheae advance ate duing slotting ( z ) 7 [m/min],
976 distance between elocated conveyo and suppot (x 2 ) 0 [m], minimal distance between elocated conveyo and sheae (p) 0 [m], distance between elocated suppot and sheae (s) 9 [m], dive unit elocation time (t 2 ) 8 [min], tuning station elocation time (t 5 ) 5 [min]. Afte suitable substitutions to fomula (20) wee made, mean flow ate of the winning steam in tested longwall face amounted fo φ 2k = 0, 29 [Mg/min]. Effective woking time detemined on the basis of shift epots and assessment of the supevisoy pesonnel in tested longwall face was kept at the level T e = 220 [min/shift]. Real daily (shift) output fo this longwall face obtained in time calculated accoding to fomula (24), amounts fo W zm = 2263,8 [Mg/shift]. Obtained daily output in function of effective woking time detemined fo conditions occuing in tested longwall face is shown in Fig. 5. It is linea elation and its diectional facto amounts fo 0,29. Diectional facto is then equal to mean flow ate of the winning steam in tested longwall face. The bigge value of diectional facto the bigge is influence of effective woking time onto obtained output (even small change of the length of effective woking time in the longwall face causes big changes of obtained output). alues of the effective woking time exceeding actual level T e is maked with geen colo (on axis x). Incease of the time T e in this longwall face (if possible) could be eflected by daily output incease, what was maked also with geen colo on axis y (potential output incease). Fig. 5. Daily output in function of effective woking time fo conditions occuing in longwall face, in which mean flow ate of the winning steam amounts fo 0,29 [Mg/min]. (Elaboated by the autho of the pesent study)
977 Mining output dop fom this longwall face is maked with ed colo if effective woking time occuing actually in the longwall face was educed. It is obviously non pofitable situation, what is maked with ed colo at the diagam. Results of elongation of the time T e of with 30 minutes is a good example illustating positive esults of elongation of effective woking time in this longwall face. Suitable calculations poved that elongation of effective woking time with 30 minutes could esult in the incease of the daily output up to the level of 2572,5 [Mg/shift], what is also maked In the diagam. 4. Final conclusions Effective woking time in the longwall face is one of the factos deciding about longwall poduction level. This key poblem compises undetaking activities making this time possibly long duing each poduction shift. This activities ae contolled by the mining plant supevisoy pesonnel and they compise: shotening of the walking (diving) time to the longwall, division of wok activities, shotening of bake downs time and woking bakes independent on the used technology, etc. The method pesented in this study can be vey useful tool fo assessment of the effective woking time in longwall face and its influence on obtained output. The developed method allows fo conditions occuing in given longwall face calculation of so called mean flow ate of the winning steam being also a diectional facto of linea function descibing dependence of daily output on effective woking time in the longwall face. Such fomulated elation pesented also in fom of the diagam pay ou attention to meaning and influence of effective woking time onto obtained mining output. It should motivate paticulaly supevisoy pesonnel because it bings evident advantages esulting fom elongation of this time, and it also shows possible losses in daily output, in case when effective woking time was shotened in given longwall face. Refeences Snopkowski R., 2000. Bounday conditions fo elementay functions of pobability densities fo the poduction pocess ealized in longwalls. Ach. Min. Sci., ol. 45, No 4, p. 50-50. Snopkowski R., 2002. Longwall output plan consideed in pobability aspect. Ach. Min. Sci., ol. 47, No 3, p. 43-420. Snopkowski R., 2005. The use of the Stochastic Simulation fo Identyfication of the Function of Output Pobability Density. Ach. Min. Sci., ol.50, No 4, p. 497-504. Snopkowski R., 2009. Stochastic model of the longwall face excavation using two-way sheae mining technology. Ach. Min. Sci., ol. 54, No 3, p. 573-585. Snopkowski R., Napieaj A., 202. Method of the poduction cycle duation time modeling within had coal longwall faces. Ach. Min. Sci., ol. 57, No 3, p. 573-585. Snopkowski R., Sukiennik M., 202. Selection of the longwall face cew with espect to stochastic chaacte of the poduction pocess pat pocedual desciption. Ach. Min. Sci., ol. 57, No 4, p. 07-088. Snopkowski R., Sukiennik M., 203. Longwall face cew selection with espect to stochastic chaacte of the poduction pocess pat 2 calculation example. Ach. Min. Sci., ol. 58, No, p. 227-240.