Drill Holes Research Articles

A New Technique of Grouting to Prevent Water–Sand Mixture Inrush inside the Mine Panel—A Case Study

Water–sand mixture inrush generally poses a significant threat to the safe operation of the quarry of coal mines. Therefore, proactive management initiatives are essential to enhance the impact resulting from mining operations. A novel approach involving grouting into the unconsolidated sand aquifer and the weathered zone was initially executed in the 1010-1 panel of the Wugou coal mine in Anhui Province, China. Considering the hydrogeological conditions of the study area, over 70 thousand tons of cement and fly ash were injected through 42 boreholes. Sampling, laboratory tests, similar materials model simulations, and numerical simulations of the trending and dipping profiles were all employed to elucidate the evolution and characteristics during the progression of the No. 10 coal seam. The outcomes illustrated that the grouting execution had transformed the structure of the porous media, weakened the watery media, and intensified the mechanical strength of the No. 4 aquifer and the weathering zone. This transformation proved beneficial in reducing the heights of the caving zone and water-conductive fracture zone, leaving more coal–rock pillars for safety. Twenty-seven underground detection drill holes and whole-space 3D resistivity exploration were adopted to verify its transformed property of low water content. During the mining process, the height of the caving zone at 19.70 m was measured through inter-hole parallel electrical detection. The pressure of hydraulic supports in the grouted area did not exceed the rated working pressure during mining. All of these findings highlight the significant impact of grouting in this study area. The successive safe mining of the 1010-1 panel demonstrates that grouting can be used to prevent water–sand mixture inrush during mining operations.

Magnetotelluric imaging of an iron-oxide copper gold (IOCG) deposit under thick cover

The presence of thick (>100 m) and electrically conductive (< 10 Ω.m) ground cover is a major impediment in mineral exploration of deep resources. Iron-oxide copper gold (IOCG) systems in Australia are often associated with a pronounced potential field anomaly, depending on the oxidation state of iron, but the gravity and magnetic field signatures have little vertical resolution unless constrained by drill hole petrophysics. Additionally, IOCG systems have deep magmatic sources, with their conductivity anomalies extending at least to the lithospheric mantle. The Vulcan IOCG prospect lies about 30 km northeast of the Olympic Dam IOCG mine and is defined by a significant gravity anomaly associated with brecciated haematite beneath 850 m of sedimentary cover sequences. To image the physical properties and structural geometry of the Vulcan IOCG prospect, a 100-site broadband MT and passive seismic array was deployed in a 1 km grid over a 9 by 9 km area. Three-dimensional inversion of MT responses resolve structure in three distinct domains. Firstly, broad limestone-quartzite-shale stratigraphy (1–30 Ω.m) in the 850 m cover is delineated in resistivity and corresponds well with changes in shear-wave velocity. Secondly, the region of brecciated haematite below the cover sequences is shown to have lower resistivity (< 60 Ω.m) than surrounding country rock (> 100 Ω.m). Thirdly, a more electrically conductive (< 30 Ω.m) vertical zone that extends > 5 km is imaged a few kilometers to the northeast of the Vulcan haematite breccia, and appears to be linked by a region of low shear-wave velocity in the depth range 1–2 km. Two-dimensional inversion of more regional MT responses along a 200-km line passing through the Vulcan prospect suggest this vertical region of low resistivity links to the lower-crust with anomalous resistivity of < 60 Ω.m in a similar way as imaged beneath the Olympic Dam mine. It is suggested that this conductive region is associated with graphite precipitated from magmatically derived CO2-rich fluids cooling in a reducing environment.

Tendon graft through the coracoid tunnel versus under the coracoid for coracoclavicular/acromioclavicular reconstruction shows no difference in radiographic or patient-reported outcomes.

The purpose of this prospective study was to report the outcomes of two different methods in CC and AC reconstruction for the treatment of AC separation using a tendon graft and knot-hiding titanium clavicular implant. Twenty-seven patients with Rockwood grade III and V acromioclavicular (AC) separations were randomized into two groups. The primary outcome was whether taking the tendon graft through the coracoid risked a fracture. The following were secondary outcomes: follow-up of clavicular wound healing and Nottingham Clavicle score, Constant score, and Simple Shoulder Test results obtained preoperatively and 24months postoperatively. The anteroposterior radiographic change between the clavicular and coracoid cortexes and the clavicular tunnel diameter was measured postoperatively and 24months postoperatively. General patient satisfaction with the outcome (poor, fair, good, or excellent) was assessed 2years postoperatively. No coracoid fractures were detected. No issues in clavicular wound healing were detected. The mean Nottingham Clavicle score increased from a preoperative mean of 42.42 ± 13.42 to 95.31 ± 14.20 (P < 0.00). The Constant score increased from a preoperative mean of 50.81 ± 17.77 to 96.42 ± 11.51 (P < 0.001). The Simple Shoulder Test score increased from a preoperative mean of 7.50 ± 2.45 to 11.77 ± 1.18 (P < 0.001). The changes were significant. The coracoclavicular distance increased from 11.88 ± 4.00 to 14.19 ± 4.71 mm (P = 0.001), which was significant. The clavicular drill hole diameter increased from 5.5 to a mean of 8.00 ± 0.75 mm. General patient satisfaction was excellent. There were no significant differences between the two groups. There were no implant related complications in the clavicular wound healing. The results support the notion that good results are achieved by reconstructing both the CC and AC ligaments with a tendon graft. This clinical trial was registered on Clinicaltrials.gov.

Natural source-field induced polarisation exploration of an iron-oxide copper-gold (IOCG) deposit under thick cover

Induced polarisation (IP) is a common geophysical method of exploration for disseminated sulphides. However, in areas with deep (>200 m) and conductive (10 Ωm or less) cover, the technique is less successful as it requires a significant transmitter source and large-offset dipoles. An alternative approach is to use natural-variations in Earth’s external magnetic field as the polarising source of the signal, known as natural-field IP. This paper presents a study of extracting IP information from electrical dipole observations during a broadband magnetotelluric (MT) program with a 9 km by 9 km grid of 100 sites above the Vulcan IOCG deposit beneath 750 m of cover, ∼40 km north of the Olympic Dam IOCG mine in South Australia. Inter-site transfer functions between 95 sites and five reference sites at the southeast and southwest corners of the grid were computed to determine a phase shift between horizontal electric fields in the bandwidth of 1–100 s period. Phase shifts of up to – 5 degrees were centred on a region of brecciated hematite where drill holes intersected pyrite, and an inferred fault-zone from passive seismics that marks the boundary between upper crust that is resistive (>100 Ω.m) with high magnetic susceptibility to the south of the fault, and a region of conductive crust (<10 Ω.m) which is low magnetic susceptibility. Our study suggests that the natural-field IP method can identify regions of polarizable minerals beneath deep cover where artificial power sources cannot be feasibly deployed. Such surveys are cheaper, safer, and easier to deploy as only receivers are required, and 3D coverage can be obtained as the source-field is of much larger dimension than the survey array. In addition, the natural-field IP signals are observed as part of the MT program so that both electrical resistivity and polarisation parameters can be determined.

Research on 3D geological modeling based on boosting integration strategy

Accurate geology modeling is critical in coal mining engineering for increasing mining efficiency and safety. Traditional 3D modeling approaches rely on drill hole data to fill in unknown geographical characteristics using interpolation or machine learning methods. However, the cost of individual borehole projects is high, and borehole distribution is sparse; the filling of sparse boreholes by interpolation smoothes the geologic data to some extent, and some abnormal geologic conditions cannot be shown in the interpolated geologic data; and the classification of subsurface space by machine learning is hampered by sparse training samples and model overfitting or underfitting. As a result, this paper proposes a method to reduce the complexity and uncertainty in the process of 3D geological modeling by integrating the classification results of multiple classifiers based on the machine learning classification model and constructing a 3D geological model based on gas extraction borehole data using the Boosting integration strategy. The results reveal that the Boosting integration model outperforms a single machine learning model in geological modeling, with improved classification accuracy and resilience. A comparative investigation of different classifiers demonstrates that the Boosting integrated model outperforms a single classifier in geological modeling. The geologic profile analysis confirms the dependability and stability of the Boosting integrated model, which can provide an effective solution for 3D geologic modeling of coal mine workings and is critical for increasing mining productivity and lowering accident risks.

3D C-arm navigated suture button implantation for AC joint dislocations - the pilot study

PurposeThe surgical treatment of acute traumatic AC joint dislocations is still a subject of scientific debate in the literature. The arthroscopically assisted stabilization procedure with a suture button system has been successfully established and is widely used in daily practice. It is minimally invasive and allows the anatomical reconstruction of the torn coracoclavicular ligaments in one step with a permanent implant that does not have to be removed in a second operation. This clinical pilot study is the first to describe the new method of navigated suture button implantation with the future aim of further reducing surgical invasiveness and further increasing surgical precision.Materials and methods10 patients with a Rockwood 3b/5 injury could be included in the prospective study (DRKS00031855) within 5 months according to inclusion and exclusion criteria. Surgical stabilization was performed with a suture button system via a navigated coracoclavicular drill tunnel. Demographic and radiological data as well as information on health and shoulder function were collected from patient records, X-rays, DVT scan and 3 questionnaires (DASH, NHS and Eq. 5D) at the preoperative, intraoperative and postoperative (discharge, 6 weeks and 3 months) time points.ResultsAll operations could be performed within 8.8 days (± 6.81) after trauma. The average operation time was 50.3 min (± 8.81). The mean distance of the drill hole in the clavicle to the AC joint was 26.6 mm (± 2.63). The radiologically measured vertical coracoclavicular distance was 38.8 mm (± 6.16) at discharge and 41.11 mm (± 7.51) at 3 months. This loss of reduction was not statistically significant. In contrast, the DASH, NHS and Eq. 5D results showed significant improvement from discharge to 3 months postoperatively.ConclusionImage-guided 3D C-arm navigated AC joint suture button stabilization is feasible in everyday surgical practice. It may be possible to achieve a further reduction in invasiveness while at the same time increasing the accuracy of implant positioning. Further clinical studies with a larger number of patients and a longer follow-up period are necessary to enable a comparison with conventional methods.

Intraoperative Doppler flowmetry evaluation of humeral head perfusion after proximal humerus fracture

Understanding vascularity and assessing the risk of post-traumatic avascular necrosis are crucial for predicting outcomes and identifying optimal treatment options in proximal humerus fractures (PHFs). Until now, Hertel etal have been the only researchers to evaluate the intraoperative perfusion of the humeral head after fracture using Doppler flowmetry in a central single drill hole within the head. This pilot study aims to standardize the evaluation of intraoperative perfusion measurements in different areas of the humeral head in patients with PHF. In this prospective pilot study, intraoperative semiquantitative Doppler perfusion measurements were conducted during plate osteosynthesis for PHF treatment in our institution between July 2021 and May 2022. The fracture morphology was classified radiologically according to Resch's criteria. Quality of reduction was determined postoperatively to be either anatomical, minor malreduced, or major malreduced according to Peters etal in conventional and computed tomography examinations. Medial hinge integrity and medial metaphyseal extension were assessed radiographically according to Hertel etal. Intraoperatively, after drilling screw holes through the plate, a Doppler probe was inserted through all nine drill holes on the humeral head and at least one on the humeral shaft to successively measure the presence of a pulse to indicate if perfusion is present. A total of ten patients (mean age 59 years, range, 36-83) with a humeral head fracture (2× 2GL, 3× 3G, 2× 4G, 2× 4GL, 1× 5aG according to Resch) were included. Nine of the ten patients showed a pulse signal on the humeral shaft. Overall, pulse-synchronous perfusion was detected using Doppler sonography in at least one hole in the humeral head of all patients. In patients with an intact medial hinge (N=6), pulse-synchronous perfusion could be measured in almost twice as many humeral head holes on average (5.7 vs. 3.0 drill holes) compared to patients with a dislocated medial hinge (N=4). In patients with metaphyseal extension (N=3), pulse-synchronous perfusion was measured in an average of 6.7 humeral head holes compared to 3.7 holes in patients without metaphyseal extension (N=7). Semiquantitative, intraoperative Doppler flowmetry offers a noninvasive and rapid assessment of humeral perfusion which allows an understanding of humeral head perfusion, when used in a standardized fashion to measure flow in different areas of the humeral head.

Fixation failure and early loss of reduction with the use of suture anchors for surgical repair of acromioclavicular joint dislocation: a case series

IntroductionSuture anchors have been used in surgical repair of acromioclavicular joint (ACJ) dislocation. While some reports indicate favorable results, others emphasize less promising outcomes. This case series reports our experience with suture anchors for surgical treatment of ACJ dislocation. MethodsClinical and radiographic outcomes in three patients treated operatively for ACJ dislocations were reviewed. In all patients, two suture anchors were inserted in the coracoid (unicortical) and #5 non- absorbable suture from the suture anchor was shuttled through drill holes in the clavicle and tied over two button devices. The coracoclavicular (CC) ligaments were reconstructed using a figure of eight semitendinosus allograft around the coracoid and clavicle. Postoperatively, sling immobilization was used for 6 weeks, and physical therapy was initiated at 6 weeks with contact activity allowed at 6 months. ResultsThree male patients underwent treatment for Rockwood type 3 (chronic; n=1) and type 5 (n=2) ACJ dislocations. Loss of reduction was noted within 6 weeks postoperatively. Two patients exhibited failure due to complete suture anchor pullout and the third patient had partial pull out of one of the anchors. Additionally, the third patient also suffered a coracoid fracture adjacent to the anchor’s placement after sustaining direct trauma to his shoulder, one-year postoperatively. ConclusionIn our case series, we found a high rate of fixation failure and early loss of reduction with the use of suture anchors for the treatment of ACJ dislocation. These findings should be taken into consideration when selecting an appropriate implant for fixation of ACJ dislocation.

Modeling and mitigation of vortex formation in ejector deep hole drilling with smoothed particle hydrodynamics

Ejector deep hole drilling achieves high-quality boreholes in production processes. High feed rates are applied to ensure a high productivity level, requiring reliable chip removal from the cutting zone for a stable process. Therefore, a constant metalworking fluid flow under high volume flow rates or high pressure is required. Experimental results show a vortex formation at the outer cutting edge. This vortex can lead to delayed chip removal from the cutting zone, and ultimately, it can lead to chip clogging and result in drill breakage due to increased torque. This paper investigates modified drill head designs using the smoothed particle hydrodynamics method. The investigated modifications include various designs of the chip mouth covering. Besides graphical analysis based on flow visualizations, flow meters are placed at the tool’s head to evaluate the impact of the modifications on the flow rate and possible increased resistance and relocation of the fluid flow from the outer cutting edge to other parts of the tool. The simulation results for the reference design show the experimentally observed vortex formation, validating the simulation model. By adding the tool’s rotation in the SPH simulation, which is not included in the experiments for observation reasons, the vortex formation is positively influenced. In addition, some designs show promising results to further mitigate the vortex formation while maintaining a sufficient fluid flow around the cutting edges.

Enhancing deep orebody prediction and localization through the revelation of geochemical primary halo patterns in drill holes

Geochemical primary halos play a crucial role in mineral exploration as they provide valuable insights into the dispersion of ore materials, identification of concealed deposits, and determination of ore deposit dimensions. The Naruo mining area in the Duolong mineral district, northern Tibet, China well-known for its worldclass porphyry-epithermal Cu–Au deposits is currently chosen as the study area. We employ statistical and nonlinear methods to analyze geochemical data from drill holes. Specifically, R-type cluster analysis is utilized to evaluate element affinity and concentration index, while an improved Grigorian zoning index is employed to delineate the vertical zoning sequence of the primary halo. These methodologies significantly enhance our understanding of element enrichment within geological contexts and greatly contribute to mineral resource evaluation. Based on these results, we have constructed a vertical zonation index model of denudation coefficient tailored to the geological characteristics of mineralization within the study area. This model effectively represents the vertical variation of the ore body. Our findings reveal a decrease in this zoning index towards the central region of deep ore bodies which correlates with deep granodiorite porphyry occurrences. Furthermore, we observe increasing concentrations of Cu, Ag, and Au with depth in specific sections of drill holes indicating promising exploration potential. Supplementary short-wave infrared data suggests the presence of a deep hydrothermal center in drill hole RNZK2404 which tentatively infers concealed porphyry bodies. Notably, the reversal observed at 4200 m on RNZK2404's zoning index hints at a possible hidden ore body at great depths. Finally, three-dimensional visualization techniques effectively illustrate spatial patterns for elements thereby paving way for future endeavors in mineral exploration.

Petrological and mineralogical characteristics of “red material layer” in Patuha geothermal field, Bandung, West Java

Abstract Patuha Geothermal Field is located in Ciwidey, Bandung, West Java Province, with a total resource potential of approximately 400 Mwe (Megawatt electric). With such potential, seven power plants have been developed in Unit-1, capable of producing 60 MWe of electricity, and are currently being developed in stages for Unit-2. In the development of the Unit-2 power plant, there was a problem where collapse occurred around the drill hole area, especially since the color of the material that came out during drilling was red. We call this material the red material layer (a layer composed of red material). This problem also occurs in Unit-1. This research aims to characterize the type of red material layer to see why this problem occurs in this layer. We studied the petrological and mineralogical characteristics of the red material layer by cutting rock samples from six drill holes in Unit-1. The analytical methods used were megascopic observation, petrography, and XRD (X-ray diffraction) to determine the mineral content texture and identify the material’s origin, including clay minerals, alteration, and oxidation mineral aggregates. The petrological and mineralogical analysis found that the red-colored material is dominated by hematite, with some samples containing magnetite. We found four characteristic types of red layer material and four types of textures that appeared in iron oxide minerals: rim, vein, matrix replacements, and fragment replacements. We conclude from the visible vein texture that oxidation occurs due to oxygen penetration through gaps of a fault/fracture/joint. This oxidizes the area around the vein and then undergoes hydrothermal change. Meanwhile, those that do not have a vein texture are considered material resulting from an oxidation process on the surface, which is then deposited and undergoes hydrothermal change to contain oxide minerals such as hematite and magnetite. Apart from that, XRD observations also found high amounts of clay minerals such as chlorite, smectite, kaolinite, illite-smectite mixed layers, and chlorite-smectite mixed layers. The presence of these clay minerals is thought to cause a collapse in the area around the drill hole because its swelling and exfoliation properties are reactive to fluids, especially drilling fluids.

Multi-Task Learning of Object States and State-Modifying Actions From Web Videos.

We aim to learn to temporally localize object state changes and the corresponding state-modifying actions by observing people interacting with objects in long uncurated web videos. We introduce three principal contributions. First, we develop a self-supervised model for jointly learning state-modifying actions together with the corresponding object states from an uncurated set of videos from the Internet. The model is self-supervised by the causal ordering signal, i.e., initial object state → manipulating action → end state. Second, we explore alternative multi-task network architectures and identify a model that enables efficient joint learning of multiple object states and actions, such as pouring water and pouring coffee, together. Third, we collect a new dataset, named ChangeIt, with more than 2600 hours of video and 34 thousand changes of object states. We report results on an existing instructional video dataset COIN as well as our new large-scale ChangeIt dataset containing tens of thousands of long uncurated web videos depicting various interactions such as hole drilling, cream whisking, or paper plane folding. We show that our multi-task model achieves a relative improvement of 40% over the prior methods and significantly outperforms both image-based and video-based zero-shot models for this problem.

Olecranon Osteotomy Exposure for Distal Humeral Fracture Treatment.

Olecranon osteotomy (OO) is commonly utilized to improve exposure when treating intra-articular distal humeral fractures. A chevron-shaped osteotomy facilitates reduction and increases surface area for healing1. Following distal humeral fracture reduction and fixation, the OO fragment is fixed with a precontoured plate. The OO technique yields comparable outcomes to alternative techniques1,2. The technique is performed as follows. (1) Imaging is reviewed and preoperative planning is performed. (2) The patient is positioned in the lateral decubitus position with the operative extremity placed over a bolster. (3) A longitudinal posterior skin incision is centered just medial or lateral to the tip of the olecranon. Full-thickness skin flaps are raised medially and laterally. (4) The ulnar nerve is identified and mobilized for later anterior subcutaneous transposition. (5) An OO is performed at the non-articular "bare area" of the trochlear notch with an oscillating saw and completed with an osteotome. (6) Open reduction and internal fixation of the distal humerus is performed. (7) The osteotomy fragment is reduced, and a precontoured plate is applied. (8) A small longitudinal slit in the distal triceps over the proximal edge of the plate decreases plate prominence and is repaired with suture. (9) The subcutaneous tissues and skin are closed in the usual manner. Alterative techniques include extra-articular OO, triceps splitting, triceps reflecting, and lateral para-olecranon combined with a medial approach. Multiple drill holes and a thin osteotome can help mitigate the kerf created by the oscillating saw. Alternative fixation methods include a predrilled 6.5-mm intramedullary screw, a tension band construct, suture fixation, or a one-third tubular plate. The OO technique provides improved exposure when compared with alternative techniques, enabling accurate reduction and fixation of distal humeral fractures1-3. Wilkinson and Stanley found that OO exposed the distal humeral articular surface to a greater degree than the triceps-splitting and triceps-reflecting approaches3. OO has not been associated with triceps weakness, unlike some of the alternative techniques2. The incidence of good-to-excellent outcomes is similar when comparing the techniques for exposure of intra-articular distal humeral fractures4. Osteotomies united in all patients in 2 reported series, totaling 84 cases1,2. Removal of symptomatic hardware used in OO fragment fixation can occur in a small subset of patients1,2. Provisionally size a precontoured plate and fix it on the olecranon to aid in later reduction and fracture fixation.The bare area is the desired position for the OO because of its natural lack of cartilage5,6. This non-articular bare area is located just distal to the deepest portion of the trochlear notch, approximately 2 to 2.5 cm distal to the olecranon tip5,6.An (apex-distal) chevron osteotomy angle of ∼130° will help to keep the osteotomy within the non-articular bare area6.Beginning on the dorsal surface of the ulna, directly posterior to the bare area, an oscillating saw is utilized to create a chevron osteotomy to subchondral bone, perpendicular to the long axis of the ulna5,6.The OO is completed by fracturing through the osteochondral surface, which leaves an irregular chondral cancellous surface that can accurately interdigitate. This facilitates later reduction and stability of the osteotomy.Anatomic articular reduction of the OO is not solely judged on the dorsal cortical bone because of the kerf removed by the saw blade. Instead, examination of the articular surface of the trochlear notch is the primary assessment of reduction.Placement of suture through the proximal portion of the plate aids in the repair of the longitudinal split of the distal triceps.Successful treatment of distal humeral fractures requires accurate reduction and rigid fixation aided by adequate exposure achieved through OO. ORIF = open reduction and internal fixationOT = occupational therapyHWR = hardware removalK-wire = Kirschner wireROM = range of motion.

Integration of Large Multielement Geochemical, Aeromagnetic, and Gravity Data to Geologically Map a Largely Covered Area: A Case Study from the Central African Copperbelt in Northern Zambia

Abstract This study provides a method to map lithology, stratigraphy, and structures in areas with limited outcrop using mineral exploration data from multielement soil geochemical surveys, airborne and ground geophysical surveys, and drill hole data sourced from multiple exploration companies and campaigns. The 45- by 50-km study area is located in the southern portion of the Congolese Copperbelt, where the regional geology, structure, and overall basin architecture were not well understood, partly due to thick saprolite cover. The results demonstrate that the integration of such data sets allows the creation of a geologically coherent map, which can then be used to investigate basin architecture and identify basin-forming structures.

Robot Cell that Allows Deep Hole Drilling

Ott-Jakob Spanntechnik has been supplied a robot cell that allows deep hole drilling to be automated and is reaping the benefits of the move

INVESTIGATION ON ABRASIVE WATER JET DRILLING HOLE FEATURES OF UHMWPE

INVESTIGATION ON ABRASIVE WATER JET DRILLING HOLE FEATURES OF UHMWPE

Optimising the placement of additional drill holes to enhanced mineral resource classification: a case study on a porphyry copper deposit

ABSTRACT In this study, we compared outcomes of optimising the placement of five additional drill holes using three geostatistical cost functions (AKV, WAKV, and CV) and the Particle Swarm Optimisation algorithm (PSO). WAKV identified locations with higher average copper grades compared to AKV. Conversely, CV suggested sites with high kriging variance and copper grade variation. Initial holes, alongside those determined by each cost function, were used to classify mineral resources. Findings underscored the effectiveness of optimising drill hole placement based on cost functions in reducing uncertainty and improving mineral resource classification.

Three-Dimensional Geologic Modeling of the Kiruna Mining District, Sweden: Insights into the Crustal Architecture and Structural Controls on Iron Oxide-Apatite Mineralization

Abstract To support economic decisions and exploration targeting, as well as to understand processes controlling the mineralization, three-dimensional structural and lithological boundary models of the Kiruna mining district have been built using surface (outcrop observations and measurements) and subsurface (drill hole data and mine wall mapping) data. Rule-based hybrid implicit-explicit modeling techniques were used to create district-scale models of areas with high disproportion in data resolution characterized by dense, clustered, and distant data spacing. Densely sampled areas were integrated with established conceptual studies using geologic conditions and the addition of synthetic data, leading to variably constrained surfaces that facilitate the visualization, interpretation, and further integration of the geologic models. This modeling approach proved to be efficient in integrating local, frequently sampled areas with district-scale, sparsely sampled regions. Dominantly S-plunging lineation on N-S–trending fracture planes, characteristic fracture mineral fill, and weak rock mass at the ore contact indicated by poor core orientation quality and rock quality description suggest that ore-parallel fractures in the Kiirunavaara area were more commonly reactivated. Slight variation in the angular relationship of fracture sets situated in different fault-bounded blocks suggests that strain accommodation across the orebodies was uneven. The location of brittle faults identified in drill core, deposit-scale structural analysis, and aeromagnetic geophysical maps indicate a close relationship between fault locations and the iron oxide-apatite mineralization, suggesting that uneven stress accommodation and proximity of conjugate fault sets played an important role in juxtaposing blocks from different crustal depths and control the location of the iron oxide-apatite orebodies.

PECVD technology deposition of high hardness a-C:H films on micro-drill surfaces: Substrate bias voltage effects

The plasma enhanced chemical vapor deposition (PECVD) technique was utilized to produce hydrogenated amorphous carbon (a-C:H) films. The overall structure of the films consists of a Cr/WC transition layer, a WC/a-C:H transition layer, and an a-C:H functional layer. The study investigated the effects of substrate bias voltages (SBVs) of −580 V, −660 V, −740 V, −820 V, and −900 V on the microstructure, mechanical, and tribological properties of a-C:H films. The findings indicate that different SBVs influence the ionic energy during the deposition of a-C:H films, consequently affecting the film growth. In this case, when the SBV is -820 V, C+ with sufficient energy will penetrate beneath the initial layer in the form of shallow injection. Therefore, compared to other experimental groups, the a-C:H films prepared under this condition have the lowest Ra value (0.42 nm), the highest sp3 CC bond content (39.88 %), the maximum hardness (31.6 GPa), the lowest friction coefficient (0.052), and the smallest wear rate (7.48 × 10−8 mm3/(N·m)), demonstrating significantly better mechanical and tribological properties. The a-C:H films, prepared at different SBVs, are deposited on micro-drill surfaces for hole drilling tests. The experimental results indicate that a-C:H films prepared at SBV of −820 V exhibit the satisfactory drilling performance due to the better mechanical and tribological properties. This is evident not only in the minimal surface wear of the film micro-drill after different drilling quantities but also by the satisfactory quality of the corresponding machined holes. The a-C:H film micro-drill prepared at SBV of −820 V exhibited larger process capability index (CPK) values for the machined holes at 500, 1000, and 2000 hole numbers of 5.449, 3.693, and 3.263 respectively. During the 2000th drill on the printed circuit board (PCB) surface, the hole wall roughness (Rz) and nail head values of the machined hole were measured to be 10.6 μm and 1.3, respectively.

Characterization of Major Complications of Bridge Plating of Distal Radius Fractures at a Level I Trauma Center.

Comminuted, markedly displaced distal radius fractures can cause instability requiring advanced stabilization with dorsal bridge plating. However, published complication rates of bridge plating widely vary. We hypothesize that complications of bridge plating of distal radius fractures are more prevalent than published rates. A retrospective review was performed on all patients at an academic level I trauma center treated with a bridge plate for a distal radius fracture from 2014 to 2022. Sixty-five wrists were included in the final analysis: average age 53 years, male 51%, average plate retention 4 months, and average follow-up 6 months. Carpal tunnel release (CTR) was performed at time of primary procedure in 7 (10%) cases. Radial height, radial inclination, dorsal tilt, and ulnar variance were all significantly improved (P < .001). Grip strength, flexion, extension, and supination were significantly limited (P < .03). Twenty-one patients (32%) developed 35 major complications requiring unplanned reoperation, including mechanical hardware-related complication (15%), deep infection (11%), nonunion/delayed union (9%), adhesions (6%), median neuropathy (6%), symptomatic arthritis (5%), and tendon rupture (2%). Plate breakage occurred in 3 patients (5%) and was always localized over the central drill holes of the bridge plate. Major complications for bridge plating of distal radius fractures were higher at our institution than previously published. Plate breakage should prompt reconsideration of plate design to avoid drill holes over the wrist joint. Signs and symptoms of carpal tunnel syndrome should be carefully assessed at initial presentation, and consideration for concomitant CTR should be strongly considered.