No (822)
Yes (153)
Used filters
(2)
Number of found documents:
975
Published from
to
Cable bolts utilization in thick seam mining
Kukutsch, Radovan; Šňupárek, Richard; Waclawik, Petr
2014 - Czech
On the basis of different field and laboratory studies, a mining method called „cable bolting based thick seam depillaring“ has been developed CSIR-CIMFR to meet the technical challenges arising during underground extraction of a thick coal seam of India. This method is based on two simple principles of rock-mass reinforcement: (a) improvement in strength of the reinforcement with increase in the confinement and (b) dilution in strength of the reinforcement under tensile condition of the host rock mass. This method is being used by a number of Indian coal mines for depillaring of total thickness (up to 7.5 m) of a thick coal seam (developed along the floor horizon) in single lift. This paper presents application of the method at Madhusudanpur 7 Pit and Incline mine. Při pracovní návštěvě Indie jsme měli možnost se seznámit se zajímavým využitím dlouhých lanových kotev při dobývání mocných slojí v černouhelném Dole Madhusudanpur (Madhusudanpur 7 Pit and Incline mine). Jak je popsáno v příspěvku, lanové kotvy, cementované po celé délce, představují jedinou výztuž chodeb v obou fázích dvoulávkového (případně třílávkového) dobývání sloje o mocnosti až 7,5 m metodou komora/pilíř s následným dobýváním pilířů. Použití této metody, vyvinuté pracovníky CIMFR Dhanbad, přineslo zvýšení stability nadloží proti používanému dobývání s nadstropem, ale především omezilo objem materiálu výztuže, který je nutno do dolu transportovat. Vzhledem k nízké kapacitě dopravní infrastruktury v těchto mělkých dolech je tento přínos výrazný.
Keywords:
thick seam mining; cable bolts; Indian mining
Available in a digital repository NRGL
Cable bolts utilization in thick seam mining
On the basis of different field and laboratory studies, a mining method called „cable bolting based thick seam depillaring“ has been developed CSIR-CIMFR to meet the technical challenges arising ...
Decade of geotechnical monitoring in Jeroným Mine (Czech Republic)
Kaláb, Zdeněk; Lednická, Markéta; Knejzlík, Jaromír; Kaláb, Tomáš
2014 - Czech
Geotechnical monitoring is realized in the Jeroným Mine from 2001. Quarterly visual observing of selected parameters started this activity; continuous digital monitoring began in 2004 using distributed monitoring system. This contribution presents fundamental results of decade of continuous geotechnical monitoring. V Dole Jeroným (ODD) je od roku 2001 realizován geotechnický monitoring. Zpočátku zahrnoval kvartální vizuální odečty vybraných parametrů, kontinuální digitální monitoring byl zahájen v roce 2004 využitím distribuovaného monitorovacího systému. Příspěvek shrnuje zásadní výsledky desetiletého kontinuálního geotechnického monitoringu.
Keywords:
medieval mine; distributed monitoring network; geotechnical monitoring
Available in a digital repository NRGL
Decade of geotechnical monitoring in Jeroným Mine (Czech Republic)
Geotechnical monitoring is realized in the Jeroným Mine from 2001. Quarterly visual observing of selected parameters started this activity; continuous digital monitoring began in 2004 using ...
Coal tonsteins and K- bentonite ( tuffs ) in Poruba Mbrs, Ostrava Formation in the Czech part of the Upper Silesian Basin ( Namur , Arnsberg )
Martinec, Petr; Horák, J.
2013 - Czech
The Poruba Mbrs (Arnsbergian, Namurian A) constitute the topmost stratum of Ostrava Fm (Mississippian: Pendleian – Arnsbergian, Namurian A). The Poruba Mbrs incorporate sequences of terrigenous sediments (K-bentonites and coal tonsteins) where a total of 13 isochronous horizons were found: they extend over larger or smaller areas and exhibit a close spatial relationship to the other faunistic horizons or coal seams located there. The horizons, which are of volcanic origin, were formed by deep transformation of acidic volcanic ash under conditions of tropical climate, either in coal tonstein environments or in terrigenous environments (K-bentonites) in absence of humine substances. The petrographic type of the volcanic ash precursor can be interpreted within the context of the discrimination diagram of Zr/TiO2 vs. Nb/Y (FLOYD & WINCHESTER, 1977). The coal tonsteins and the K-bentonites correspond to the same type of volcanic material for which the points of projection of chemical analyses fall within the field bounded by rhyodacite to dacite, near the boundary with the andesite field. Produktů synsedimentárního vulkanismu v porubských vrstvách si povšimnuli v 60tých letech při průzkumu vrty z povrchu pracovníci tehdejšího Uhelného průzkumu Ostrava (později Geologického průzkumu Ostrava, n.p. (dále jen GPO). Výsledky shrnuje ve své disertační práci TOMŠÍK (1966). Popisuje uhelné tonsteiny slojí, které se dnes označují č. 479 OKD a 495 OKD. Horniny vulkanogenního původu, argilitizované v terigenním prostředí na K-bentonity (tufity) nalezl 20 metrů pod bází „zámeckého slepence“ z oblasti Dětmarovic (410 OKD). Dále popisuje horizont z podloží mořského horizontu Gabriely (418 OKD) z oblasti Frenštátu. Paralelně byl prováděn průzkum uhelných tonsteinů - na katedře geologie a mineralogie VŠB v Ostravě J. Králíkem, který ve své habilitační práci (KRÁLÍK 1969) popisuje uhelné tonsteiny slojí 424 OKD, 452 OKD, 479 OKD a 495 OKD. Stejnými horizonty z porubských vrstev se zabývají dále práce KRÁLÍK (1972) A DOPITA & KRÁLÍK 1977. Detailně popisují výskyty uhelného tonsteinu sloje č. 495 OKD z Karvinska ŠPACHMAN & HORÁK 1989.
Keywords:
coal tonsteins; Poruba Mbrs; Ostrava Formation
Available in a digital repository NRGL
Coal tonsteins and K- bentonite ( tuffs ) in Poruba Mbrs, Ostrava Formation in the Czech part of the Upper Silesian Basin ( Namur , Arnsberg )
The Poruba Mbrs (Arnsbergian, Namurian A) constitute the topmost stratum of Ostrava Fm (Mississippian: Pendleian – Arnsbergian, Namurian A). The Poruba Mbrs incorporate sequences of terrigenous ...
Texture of cokes in relation to parameters of coal and coke
Pěgřimočová, J.; Kožušníková, Alena
2013 - English
The article presents a proposal of the simplified classification of textures of coke and the relationship between the texture parameters of coke both coal, from which the coke was made, and properties of the coke.
Keywords:
texture of cokes; coal; phase carbon forms
Available in a digital repository NRGL
Texture of cokes in relation to parameters of coal and coke
The article presents a proposal of the simplified classification of textures of coke and the relationship between the texture parameters of coke both coal, from which the coke was made, and ...
Pulsed liquid jet generated by pulse multiplication technique
Dvorský, R.; Sitek, Libor; Sochor, T.
2013 - English
First theoretical papers summarizing the high mechanical energy cumulation when high-speed drops impacting the solid surface as a result of the water hammer effect have been known since 1960’s. Heymann has demonstrated that pressure maximum in the impact of a spherical drop of a liquid is several times higher than the presupposed maximum for the classical water hammer effect. The latter maximum pressure itself exceeds the mere stagnation pressure of the continuous jet many times hereat. When developing devices for pulse jet generation a new generalization of the classical water hammer theory for high pressures has been implemented. Based on this the new patented principle of “pulse multiplication” has been formulated. The pulse multiplier is the source of high-pressure pulses with 100% depth of modulation of liquid jet discharge velocity that allows increasing the jet disintegration effect significantly without the abrasive material application.
Keywords:
pulse liquid jet; water hammer effect; pulse intensifier; high-pressure pulses
Available in a digital repository NRGL
Pulsed liquid jet generated by pulse multiplication technique
First theoretical papers summarizing the high mechanical energy cumulation when high-speed drops impacting the solid surface as a result of the water hammer effect have been known since 1960’s. ...
Preliminary analysis of volume material removal at bone cement disintegration by pulsating water jet
Lehocká, D.; Hloch, S.; Foldyna, Josef; Monka, P.; Monková, K.; Brezíková, K.
2013 - English
The article deals with preliminary analysis of material removal during disintegration of bone cement. This article was created to show possibilities of pulsating water jet utilization in medicine. Experiments with pulsating water jet were done using two types of nozzles - flat and round. Traces in bone cement were measured by optical profilemeter MicroProf FRT. Results show that pulsating water jet will be possible focuses as a tool for medical purposes, but further detailed research is needed.
Keywords:
pulsating water jet; PMMA - bone cement; volume removal
Available in a digital repository NRGL
Preliminary analysis of volume material removal at bone cement disintegration by pulsating water jet
The article deals with preliminary analysis of material removal during disintegration of bone cement. This article was created to show possibilities of pulsating water jet utilization in medicine. ...
Research on effects of pulsating water jets on concrete
Sitek, Libor; Bodnárová, L.
2013 - English
An article briefly presents results achieved during laboratory and in-situ tests of removing surface layers of concrete exposed to various environments using several types of high-velocity water jets commonly used in the rehabilitation praxis or advanced water jets the use of which is expected in the near future. The effects of pulsating jets were always compared with classical continuous jets under identical or similar working conditions.
Keywords:
degraded concrete; structure rehabilitation; concrete surface; pulsating water jet
Available in a digital repository NRGL
Research on effects of pulsating water jets on concrete
An article briefly presents results achieved during laboratory and in-situ tests of removing surface layers of concrete exposed to various environments using several types of high-velocity water jets ...
Removal of polyurea spray coatings from the surface of cement concrete by water jet technology
Ščučka, Jiří; Bódi, Z.; Hlaváček, Petr; Klich, Jiří; Martinec, Petr; Foldyna, Josef
2013 - English
The paper is focused on the removal of polyurea spray coatings from the surface of cement concrete by the water jet technology. A series of experiments was conducted to disintegrate a defined polyurea spray coat layer on the surface of cement concrete tiles using different configurations of the water jet system. The results of these experiments have confirmed that the continuous water jet was highly effective in removing the spray coat, causing no damage to the concrete substrate underneath. The partial experimental results have also indicated that this process can be used to produce an anti-skid finish on polyurea spray coatings applied onto horizontal structures.
Keywords:
concrete; polyurea spray coating; removal; water jet
Available in a digital repository NRGL
Removal of polyurea spray coatings from the surface of cement concrete by water jet technology
The paper is focused on the removal of polyurea spray coatings from the surface of cement concrete by the water jet technology. A series of experiments was conducted to disintegrate a defined polyurea ...
Contemporary problems and research opportunities of the environmental geomorphology in the Czech Republic
Kirchner, Karel
2013 - Czech
This paper is focused on the position of the environmental geomorphology and the current state of knowledge in the Czech Republic. The basic outline of research approaches and opportunities to extend its research concept are presented. Research concept of environmental geomorphology is extended by evaluation of geomorphological sites (geomorphosites) owing to experiences of the investigation in the territories in Moravia. Příspěvek se zaměřuje na postavení environmentální geomorfologie a současný stav jejího poznání v České republice. Je uveden základní přehled přístupů a možností výzkumu pro rozšíření výzkumného koncepce. Výzkumný koncept environmentální geomorfologie je rozšířen o hodnocení geomorfologických lokalit díky výzkumným poznatkům, získaným v různých územích Moravy.
Keywords:
environmental geomorphology; geomorphosites; research approaches; the Czech Republic
Available in a digital repository NRGL
Contemporary problems and research opportunities of the environmental geomorphology in the Czech Republic
This paper is focused on the position of the environmental geomorphology and the current state of knowledge in the Czech Republic. The basic outline of research approaches and opportunities to extend ...
Relief assessment methodology with respect to geoheritage based on example of the Deblínská vrchovina Highland
Kirchner, Karel; Kubalíková, L.
2013 - English
The article deals with history, presence and possible future development of geoconservation in the Czech Republic. Both examples of legislative instruments and other geoconservation activities are presented. Practically, the geoconservation activities are shown at the case study of the central part of the Deblínská vrchovina Highland (Maršov valley area) in the south-eastern part of the Czech Republic.
Keywords:
geoheritage; geomorphosites assessment; Maršov valley
Fulltext is available at external website.
Relief assessment methodology with respect to geoheritage based on example of the Deblínská vrchovina Highland
The article deals with history, presence and possible future development of geoconservation in the Czech Republic. Both examples of legislative instruments and other geoconservation activities are ...
NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web
Send your suggestions and comments to nusl@techlib.cz
Provider
Other bases