Combined support mechanism of rock bolts and anchor cables for adjacent roadways in the external staggered split-level panel layout

Using the spatial structure of the external staggered split-level panel layout, a combined support technology for adjacent roadways was developed and analyzed for a rock bolt and anchor cable mechanism. The influence of the side rock bolt and anchor cable parameters on the mechanical properties of the anchorage body and the support stress distribution of the lateral coal body were revealed using the FLAC3D software. The optimal support parameters of the side rock bolts and anchor cables were subsequently determined, and the support effect of gob-side entry in a mining scenario was verified. The results show that the support of the side rock bolts and anchor cables improves the mechanical properties and stress state of the anchorage body, producing a good protective effect on the coal body of the air-intake entry roof and side wall. This is beneficial to the stability of the side wall and the realization of the suspension effect for roof rock bolts and anchor cables, which in turn makes the surrounding rock maintenance of the gob-side entry to a thick coal seam more favorable.

Study on Eccentric Uncoupled Blasting Effect of Cutting Seam Pipe

In order to study the blasting effect and the damage to the rock mass when the cutting seam cartridge is eccentrically and uncoupled. The ANSYS/LS-DYNA® nonlinear dynamic platform was used to simulate the blasting effect of five eccentric uncoupled coefficients on the cutting seam cartridge, and the crack growth process under the condition of complete eccentricity was simulated. By comparing and analyzing the stress of measuring points in the direction of cutting seam, vertical cutting seam direction, and circumferential cutting seam pipe under different working conditions. It is concluded that the effect of detonation products is affected by the wrapping property of the cutting seam pipe and the eccentric uncoupled coefficient. With the increase of the eccentric uncoupled coefficient, the load distribution presents obvious non-uniformity. The pressure on the uncoupled side of the blasthole is smaller than that on the coupled side, and the peak time of the uncoupled side also lags behind that on the coupled side. When the eccentric uncoupled coefficient is 1, the peak pressure on the coupled side is 5.78 times that of the uncoupled side, and the explosive stress field is biased toward the coupled side. The existence of the cutting seam pipe causes stress concentration at the opening, which enhances the guiding effect of the initial crack, and the stress in the non-cutting seam direction is buffered. Therefore, the eccentric arrangement of the cutting seam pipe determines the formation of the initial crack and the subsequent blasting effect. When the cutting seam cartridge is arranged eccentrically and uncoupled, it will cause under-excavation at the connection direction of blasthole, which will cause less disturbance to the rock mass on the uncoupled side. If the retaining side rock mass is on the coupled side in actual blasting, the eccentric uncoupled arrangement will cause greater over-excavation and damage. Therefore, it is necessary to avoid this situation as far as possible and provide better guidance for the actual construction.

An Experimental and Numerical Investigation on the Initiation and Interaction of Double Cracks in Rocks under Hydromechanical Coupling

The growth of double cracks is the main factor leading to progressive rock failure under hydromechanical coupling. The initiation modes and interaction behaviors of double cracks were investigated by using laboratory tests, and the influences of water pressure were analyzed. The maximum energy release rate criterion was modified to determine the crack growth characteristics. A numerical model was established and then verified by the test results. Based on the simulation, the distribution of stress fields and key fracture parameters of double cracks was investigated. Then, initiation characteristics and interaction behaviors of parallel and nonparallel cracks were quantitatively analyzed. The results indicate that the increase in water pressure leads to the crack initiation being inclined to the original surfaces and the growth length along the crack fronts tending to be uniform; the small tensile stress zones are formed close to the crack tips, and significant compressive stress zones are formed at both sides of the crack surfaces; stress superposition and interaction occur when crack spacing is less than 2.5a; the interactive weakening effect is mainly present in the inner side (rock bridge zone) of cracks, while a certain degree of interactive enhancement effect exhibits in the outer sides; the cracks are much easier to initiate at the outer wing cracks when the spacing is less than the critical length (0.5a); and cracks with a dip angle of 45° are much easier to initiate at the endpoints of long axis. The research results provide certain theoretical guidance for the safety assessment of underground engineering.

Combined support mechanism of rock bolt and anchor cable for adjacent roadways in the external staggered split-level panel layout

Utilizing the spatial structure characteristic of the external staggered split-level panel layout, the combined support technology of adjacent roadways was proposed, and combined support mechanism of rock bolt and anchor cable was analyzed. The influence of side rock bolt and anchor cable parameters respectively on mechanical properties of the anchorage body and support stress distribution of lateral coal body were revealed through FLAC 3D software. The optimal support parameters of side rock bolt and anchor cable were determined subsequently. And the support effect of the gob-side entry under mining influence was verified. Result shows that the support of side rock bolt and anchor cable can improve mechanical properties and the stress state of the anchorage body, which has a good protective effect on the coal body of the air-intake entry roof and side wall. It is beneficial to the stability of the side wall and the realization of the suspension effect for the roof rock bolt and anchor cable, which makes the surrounding rock maintenance of the gob-side entry of the thick coal seam more favorable.

Geological and geochemical signs and criteria of potential mineralization in the Tangaralakh intrusion

The scope of the discussion embraces the problems connected with development and improvement of geological information processing methods and systems, as well as modeling of primary mineral deposits in exploration of side rock mass and deep horizons of the deposits under mining and in new areas with intent to discover potential copper-nickel sulphide mineralization. The target of the research is the geological and geochemical preconditions and signs of sulphide mineralization in the potentially ore-bearing Tangaralakh field adjacent to the deposits of the Talnakh ore-magmatic system. The integrated research is based on the conventional different-rank geological, geochemical, magmatic, structural, tectonic, lithological and stratigraphical preconditions and signs of sulphide copper-nickel platinum-bearing ore in the Norilsk Region. The geochemical search of ore objects in the Norilsk Region provided the best results in case of the geological and structural analysis of spatial interactions between geochemical abnormalities as the geochemical zonality is yet the chief factor in the mineralization prediction. This method of improvement of geological-geochemical information processing and modeling of mineral deposits was tested in geological-geochemical modeling of the Talnakh ore province bodies. From the research findings, the structural and tectonic conditions of localization of the potentially ore-bearing Tangaralakh intrusion were determined. The structural modeling of geochemical field of the mineralization revealed the types of geochemical associations marking different compositions of sulphide mineralization in disseminated ore in different sections of the Tangaralakh intrusion. It is found that the geochemical zonality coincides with the mineral zonality of the disseminated ore horizon formed at different stages of orogenesis. The similarity elements are found in the geological-geochemical models of the Tangaralakh potentially ore-bearing ore field and Talnakh ore field (ore-magmatic system).

Combined support mechanism of rock bolt and anchor cable for adjacent roadways in the external staggered split-level panel layout

Utilizing the spatial structure characteristics of the external staggered split-level panel layout, the combined support technology of adjacent roadways is proposed, and combined support mechanism of rock bolt and anchor cable were analyzed. The influence of the side rock bolt and anchor cable parameters respectively on the mechanical properties of the anchorage body and support stress distribution of lateral coal body was revealed through FLAC3D software. The optimal support parameters of side rock bolt and anchor cable were determined subsequently. And the support effect of the gob-side entry under mining influence was verified. Result shows that the support effect of side rock bolt and anchor cable can improve the mechanical properties and the stress state of the anchorage body, which has a good protective effect on the coal body of the air-intake entry roof and side wall. It is beneficial to the stability of the side wall and the realization of the suspension effect for the roof rock bolt and anchor cable, which makes the surrounding rock maintenance of the gob-side entry of the thick coal seam more favorable.

FORAMINIFERA ASSEMBLAGES AS A MARKER OF MUD ERUPTION SOURCE IN CIUYAH, CINIRU – KUNINGAN, WEST JAVA

Mud eruptions that rise claystone to sandstone-size fragments, liquid, gas, and heat to the surface have been identified in Ciuyah, Ciniru District, Kuningan. Field observation and sampling were conducted on host rock as well as mud in Ciuyah. Forty-two planktic and forty-two benthic foraminiferal species were identified in rock samples; while 89.28% of them are recorded in mud samples. Foraminifera contained in claystone and sandstone of Pemali and Halang Formations reveals the age of Middle to Late Miocene. Based on their stratigraphic ranges, planktic foraminifera assemblages in mud represent four age-marker groups, there are: older than Zone N.10 / Middle Miocene (indicated by the appearance of Globorotalia archeomenardii), ranges of Zone N.11 – N.12 / Middle Miocene (marked by the appearance of Globorotalia fohsi lobata and Globorotalia praemenardii), ranges of Zone N.13–N.14 / Middle Miocene (Globorotalia siakensis and Globorotalia mayeri), and ranges of Zone N.15–N.17 / Late Miocene (Globorotalia acostaensis acostaensis and Neogloboquadrina dutertrei dutertrei). Benthic foraminifera can be grouped into outer neritic and bathyal typical assemblages. That several age-marker planktic foraminifera groups mixing and deep marine typical benthic occurrence in mud samples is produced by reworking process during turbidity sedimentation, as well as erosion and elution of base- and side-rock composed by Pemali and Halang Formations.Semburan lumpur yang membawa fragmen-fragmen berukuran batulempung hingga batupasir, cairan, gas dan panas ke permukaan telah teridentifikasi di Ciuyah, Kecamatan Ciniru, Kuningan. Observasi lapangan dan pengambilan sampel dilakukan terhadap batuan induk serta lumpur di Ciuyah dan sekitarnya. Empat puluh dua spesies foraminifera planktik dan empat puluh dua spesies bentik teridentifikasi dalam sampel batuan; dengan 89,28% di antaranya terekam dalam sampel lumpur. Foraminifera yang terkandung dalam batulempung dan batupasir Formasi Pemali dan Halang menunjukkan umur Miosen Tengah hingga Akhir. Berdasarkan rentang stratigrafinya, kumpulan foraminifera planktik dalam lumpur menunjukkan empat kelompok penanda umur, yaitu: lebih tua dari Zona N.10 / Miosen Tengah (ditunjukkan oleh kehadiran Globorotalia archeomenardii), rentang Zona N.11 - N.12 / Miosen Tengah (ditandai oleh kehadiran Globorotalia fohsi lobata dan Globorotalia praemenardii), rentang Zona N.13 -N.14 / Miosen Tengah (Globorotalia siakensis dan Globorotalia mayeri), dan rentang Zona N.15 - N.17 / Miosen Akhir (Globorotalia acostaensis acostaensis dan Neogloboquadrina dutertrei dutertrei). Foraminifera bentik dapat dikelompokkan dalam kumpulan neritik luar dan batial. Beberapa kelompok penanda umur foraminifera planktik dan kehadiran bentik laut dalam pada lumpur dihasilkan oleh pengerjaan ulang selama sedimentasi turbidit, serta erosi dan elusi batuan dasar dan batuan samping yang tersusun oleh Formasi Pemali dan Halang.

PENYELIDIKAN GEOMAGNET BIJIH BESI DI WILAYAH JORONG KOTA BIRAH, KECAMATAN SUNGAI PAGU KABUPATEN SOLOK SELATAN

The measureable magnetic field intensity variation is then interpreted in the form of the distribution of the magnetic material below the surface, then used as the basis for the prediction of possible geological conditions observed. The iron ore deposits in the survei area are generally interpreted as a form of sediment that fills the rock cavities, especially in limestone cavities. This occurs due to the geological structure that gives space for the placement of mineralization of ore deposits in the side rock zone. The value of this magnetic anomaly is located in the west, the eastern, and also in the north part. Keywords: Geomagnet Method, Iron Ore, Magnetic Properties, Magnetic Value, Magnetic Anomaly Value.