Journal articles: 'Drill core'

1

Tsao, Chung Chen, Kei Lin Kuo, I. Chien Hsu, and G. T. Chern. "Analysis of Core-Candlestick Drill in Drilling Composite Materials." Key Engineering Materials 419-420 (October 2009): 337–40. http://dx.doi.org/10.4028/www.scientific.net/kem.419-420.337.

Full text

Abstract:

Unlike ductile metals cutting mechanism, the interfaces between fiber and matrix as a transitional layer experience mismatched deformation in machining process. In general, the most frequent operation performed on composite materials is drilling with a twist drill to generate a hole owing to their versatility and low production cost. However, delamination is one of the most common defects in drilling laminated fiber-reinforced composites and can cause a significant reduction in the load-carrying capacity of a structure. At the periphery, using such special drills as saw drill, candlestick drill and core drill, reducible to causing delamination damage than the twist drill. Experimental results indicated that the diameter ratio and feed rate have statistical and physical significance on the thrust force obtained with a core-candlestick drill.

APA, Harvard, Vancouver, ISO, and other styles

2

Kojima, Yuto, Ryutaro Tanaka, Yasuo Yamane, Katsuhiko Sekiya, and Keiji Yamada. "Drilling of CFRP with an Electrodeposited Diamond Core Drill – Effects of Air Assistance and Tool Shape –." International Journal of Automation Technology 10, no. 3 (May 2, 2016): 310–17. http://dx.doi.org/10.20965/ijat.2016.p0310.

Full text

Abstract:

This research was conducted to investigate the characteristics of electrodeposited diamond core drills when used to cut CFRP.An eccentric core drill was usedto improve cutting characteristics. First of all, the cutting characteristics of a normal core drill were investigated at a few different feed rates and compared with those of a diamond coated twist drill. The effect of air assistance on chip evacuation were also investigated. The cutting forces, surface roughness profile of the hole, and tool appearance were used for evaluation. At the same feed rate, more cutting force was necessary for the normal core drill than for the twist drill. When air was blown in, the cutting forces required by the core drill decreased drastically, but delamination was evident. When air was drawn out, the cutting forces of the normal core drill were almost the same as when there was no air assistance. On the other hand, when an eccentric core drill was used, the cutting force required was lower when air was drawn out than when it was blown in. Additionally, the surface quality of the hole when air was drawn out was greater than when it was blown in. When the eccentric core drill with slits was used while air was drawn out, the cutting forces, surface quality of the hole, and tool appearance were the same as when an eccentric core drill without slits was used. However, there was little core jamming. Therefore, the eccentric core drill with slits had the longest tool life.

APA, Harvard, Vancouver, ISO, and other styles

3

Popp, Trevor J., Steffen B. Hansen, Simon G. Sheldon, and Christian Panton. "Deep ice-core drilling performance and experience at NEEM, Greenland." Annals of Glaciology 55, no. 68 (2014): 53–64. http://dx.doi.org/10.3189/2014aog68a042.

Full text

Abstract:

AbstractThe NEEM deep ice-core drilling in northwest Greenland was completed in summer 2010 after three seasons, which included establishing all drilling infrastructure. Normal drilling operations in the main borehole were declared terminated at 2537.36 m below the surface, when further penetration was stopped by a stone embedded in the ice in the path of the drill head. The design and implementation of the drilling operation strongly resembled the NGRIP drilling program. The NEEM drill was an extended version of the Hans Tausen (HT) drill, with specific modifications to optimize its use with the highly viscous Estisol-240/Coasol drill fluid used at NEEM. Modification to the drill and its performance in the new drilling fluid was largely satisfactory and successful. Throughout the drilling, special consideration was given to the way chips were transported and collected in a new chip chamber, including the consequences of drilling a larger borehole diameter than with previous drill operations that used the HT family of drills. The problems normally associated with warm ice drilling near the base of an ice sheet were largely absent at NEEM.

APA, Harvard, Vancouver, ISO, and other styles

4

Kojima, Yuto, Ryutaro Tanaka, Yasuo Yamane, Katsuhiko Sekiya, and Keiji Yamada. "Wet Core Drilling of CFRP with an Electrodeposited Diamond Core Drill - Effects of Cutting Conditions on Chip Evacuation and Core Jamming." Key Engineering Materials 749 (August 2017): 58–64. http://dx.doi.org/10.4028/www.scientific.net/kem.749.58.

Full text

Abstract:

This study investigated the cutting characteristics of electrodeposited diamond core drill when used to drill a CFRP under wet condition. The effects of different tool shapes, grain sizes and feed rates were examined. A normal core drill, an eccentric with slits core drill (E.S.), and an eccentric with slits and chamfers core drill (E.S.C.) were used. The normal core drill had the shape of a hollow cylinder. The E.S. core drill had the inner cylinder shifted from the center of this tool and slits in the bottom of this tool. The E.S.C. core drill had chamfers on the periphery of this tool. The normal core drill caused severe workpiece core jamming even at 1st hole drilling, and its electro-deposited area was covered entirely by adhered chips. In the case of the E.S. core drill and E.S.C. core drill, the workpiece core did not jam and the thrust force was smaller than that of the normal core drill. The effect of chamfers was little. The E.S.C. core drill with #200 caused smaller surface roughness than that with #100. However, the thrust force was two times larger, and the delamination was observed at the exit point of the hole. In the lower feed rate per revolution the better surface roughness and the lower thrust force were obtained irrespective of the tool shape while the cutting speed showed little effect.

APA, Harvard, Vancouver, ISO, and other styles

5

Hong, J., P. Talalay, M. Sysoev, and X. Fan. "DEM modeling of ice cuttings transportation by electromechanical auger core drills." Annals of Glaciology 55, no. 68 (2014): 65–71. http://dx.doi.org/10.3189/2014aog68a002.

Full text

Abstract:

AbstractElectromechanical auger core drills are widely used in shallow ice-coring practice on mountain glaciers and polar ice caps and sheets. Generally, these drills are lightweight, can be readily transported to remote drilling sites, are easily installed there and drill with relatively high rates of penetration and low power consumption. During the past few decades, dozens of electromechanical auger drills have been designed. However, the auger options were usually determined by experience, and the main parameters (auger angle and rotation speed) are varied in a wide range from drill to drill. In order to choose the optimal auger parameters, the discrete element method (DEM) is used to analyze the performance of cuttings transportation for different rotation speeds in the range 50–200 rpm and auger angles in the range 15–45°. To improve the efficiency of cuttings transportation, many factors have to be considered (e.g. particle sizes and their variability, ice temperature, material of the core barrel and jacket, and availability of needed driven motor-gears). For the conditions assumed in the present studies, the recommended rotation speed is 100 rpm at auger angles of 35–40°.

APA, Harvard, Vancouver, ISO, and other styles

6

Schwikowski, Margit, Theo M. Jenk, Dieter Stampfli, and Felix Stampfli. "A new thermal drilling system for high-altitude or temperate glaciers." Annals of Glaciology 55, no. 68 (2014): 131–36. http://dx.doi.org/10.3189/2014aog68a024.

Full text

Abstract:

AbstractFor ice-core drilling on high-elevation glaciers, lightweight and modular electromechanical (EM) drills are used to allow for transportation by porters or pack animals. However, application of EM drills is constrained to glaciers with temperatures well below the ice melting point. When drilling into temperate ice, liquid water accumulates in the borehole, hindering chip transport, filling the chip barrel and finally blocking the drill. Drilling into near-temperate ice is also problematic as pressure-induced melting can cause refreezing of meltwater on the drill which then easily gets stuck in the borehole. We developed a thermal drill compatible with the Fast Electromechanical Lightweight Ice Coring System (FELICS). The melting element consists of a coil heater, molded in an aluminum crown. Using the combined mechanical and thermal drill we obtained a 101 m surface-to-bedrock ice core from temperate Silvrettagletscher, Swiss Alps. The borehole with temperatures around 0°C was filled with meltwater. Power was supplied by two 2kW gasoline generators consuming a total of 70 L of alkylate fuel. Ice-core production rate was 1.8 mh−1. The drill produced non-fractured ice cores of excellent quality with a length of 70 cm and a diameter of 75–80 mm.

APA, Harvard, Vancouver, ISO, and other styles

7

Liu, Qiong, Guoqin Huang, and Yongchao Xu. "Investigation of drilling 2D C<sub>f</sub>∕C–SiC composites with brazed diamond core drills." Mechanical Sciences 11, no. 2 (October 12, 2020): 349–56. http://dx.doi.org/10.5194/ms-11-349-2020.

Full text

Abstract:

Abstract. Drilling carbon fiber reinforced silicon carbide composites still forms a big challenge for machining because of their special braided structure and anisotropy. In this study, through the drilling of 2D Cf∕C–SiC composites, two kinds of brazed diamond core drills with different abrasive distributions were compared. The results showed that the drilling force and torque of the two drills decreased with the increase in the spindle speed and increased with the increase in the feed speed. Under the same drilling conditions, the drilling force and torque of the brazed diamond drill with the ordered abrasive distribution were far lower than those of the brazed diamond drill with the random abrasive distribution. Also, the quality of the holes drilled by the drill with the ordered abrasive distribution was better than that of the holes drilled by the drill with the random abrasive distribution, which is attributed to the uniform abrasive spacing provided by the drill with the ordered abrasive distribution.

APA, Harvard, Vancouver, ISO, and other styles

8

Lopez-Diaz, Fernando, and Fernando Bastida. "Structural data from drill core." Geological Magazine 131, no. 5 (September 1994): 619–23. http://dx.doi.org/10.1017/s0016756800012401.

Full text

Abstract:

AbstractA graphical method for the analysis of the orientation of planar and linear structural elements in drill core is presented. Simple computation and projection operations applied to data taken from elements traced on the cylindrical surface of the core are required. To know a structural element(s) of reference, the method requires detailed structural analysis of the surface geology around the drill hole.

APA, Harvard, Vancouver, ISO, and other styles

9

Vasil’yev, N. I., B. B. Kudryashov, P. G. Talalay, and V. K. Chistyakov. "Core drilling by electromechanical drill." Polar Record 29, no. 170 (July 1993): 235–37. http://dx.doi.org/10.1017/s0032247400018556.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Lackie, M. A., and P. W. Schmidt. "Drill Core Orientation using Palaeomagnetism." Exploration Geophysics 24, no. 3-4 (September 1993): 609–13. http://dx.doi.org/10.1071/eg993609.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Lemy, F., J. Hadjigeorgiou, P. Côté, and X. Maldague. "Image analysis of drill core." Mining Technology 110, no. 3 (December 2001): 172–77. http://dx.doi.org/10.1179/mnt.2001.110.3.172.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Talalay, P. G. "Perspectives for development of ice-core drilling technology: a discussion." Annals of Glaciology 55, no. 68 (2014): 339–50. http://dx.doi.org/10.3189/2014aog68a007.

Full text

Abstract:

AbstractMore than 170 years ago, Louis Agassiz, one of the creators of glacial theory, made his first attempt to drill into the bed of Unteraargletscher, Swiss Alps. Since that time, various systems for thermal and mechanical drilling have been designed especially for boring into ice, and some conventional drill rigs been adopted for ice coring. Although contemporary ice-drilling knowledge and techniques are now familiar, there remain many problems to be solved by advanced modern technology. Specific challenges related to improving old drilling methods and developing new emerging technologies include: (1) identification of depth limitation of ‘dry’ drilling; (2) improvement of casing; (3) searching for the new environmentally friendly low-temperature drilling fluids; (4) reliable elimination of sticking drills; (5) improvement of core quality in the brittle zone; (6) additional core sampling from borehole walls after the core has been drilled; (7) obtaining oriented core; (8) designing automation drilling systems; (9) developing rapid-access drills. Possible ways of solving these problems are presented below.

APA, Harvard, Vancouver, ISO, and other styles

13

Zagorodnov, V., L. G. Thompson, and E. Mosley-Thompson. "Portable system for intermediate-depth ice-core drilling." Journal of Glaciology 46, no. 152 (2000): 167–72. http://dx.doi.org/10.3189/172756500781833304.

Full text

Abstract:

AbstractA lightweight, portable drilling system for coring up to 500 m depths has been developed and field-tested. The drilling system includes four major components: (1) an electromechanical (EM) dry-hole drill; (2) an ethanol thermal electric drill; (3) a drill set-up with a 500 m cable capacity; and (4) a controller unit. The system may be switched quickly from a dry-hole EM drill to an antifreeze thermal electric drill. This lightweight system makes ice-core drilling more cost-efficient, and creates a minimal environmental impact. The new EM drill, which recovers 100 mm diameter, 1 m long pieces of ice core, is 3.2 m long and weighs 35 kg. This drill and the drilling set-up were recently tested at the Raven (former Dye 2) site, southern Greenland, where a core was recovered to 122 m. The thermal drill is 2.9 m long and weighs 25 kg. It produces 100 mm diameter, 2.1 m long pieces of ice core, and was tested to 315 m in Franz Josef Land, Eurasian Arctic. The drilling set-up with a 250 m cable weighs about 100 kg (or 128 kg for 500 m of cable). After minor adjustments this drill system retrieved cores of better quality than those recovered by other drill systems under similar glaciological conditions. After adjustments to optimize its performance, the drill retrieved 5.25 m of core per hour over the depth range 0–21 m.

APA, Harvard, Vancouver, ISO, and other styles

14

Kuhl, Tanner W., Jay A. Johnson, Alexander J. Shturmakov, Joshua J. Goetz, Chris J. Gibson, and Donald A. Lebar. "A new large-diameter ice-core drill: the Blue Ice Drill." Annals of Glaciology 55, no. 68 (2014): 1–6. http://dx.doi.org/10.3189/2014aog68a009.

Full text

Abstract:

AbstractThe Blue Ice Drill (BID) is a large-diameter agile drill system designed by the Ice Drilling Design and Operations group of the University of Wisconsin–Madison to quickly core-clean 241 mm diameter ice samples from near-surface sites. It consists of a down-hole motor/gear reducer rotating a coring cutter and core barrel inside an outer barrel for efficient cuttings transport in solid ice. A variable-frequency drive and custom control box regulates electrical power to the drill. Torque reaction is accomplished on the surface via handles attached to a torsion stem. Core recovery is achieved with either core dogs in the sonde or with a separate core recovery tool. All down-hole tools are suspended on a collapsible tripod via ropes running on a capstan winch. The BID is operated by a minimum of two people and has been used successfully during two seasons of coring on a blue ice area of Taylor Glacier, Antarctica. An updated version of the drill system, BID-Deep, has been designed to recover cores to depths up to 200 m.

APA, Harvard, Vancouver, ISO, and other styles

15

Mu, Juan, Jiu Hua Xu, Yan Chen, and Yu Can Fu. "CFRP Drilling with Brazed Diamond Core Drill." Solid State Phenomena 175 (June 2011): 27–32. http://dx.doi.org/10.4028/www.scientific.net/ssp.175.27.

Full text

Abstract:

Despite the facts that carbon fiber reinforced plastics (CFRP) components are mostly produced near net shape, machining, especially drilling is often required in order to bring the component into dimensional requirements and prepare it for assembly. Rapid drill wear and serious machining defects are the key problems in CFRP drilling, and employing proper drill is an effective way to solve these problems. In this paper, tests of the brazed diamond core drill are presented and the related issues, such as the thrust force, the drilling quality and the drill wear are studied.

APA, Harvard, Vancouver, ISO, and other styles

16

Bright, S., G. Conner, A. Turner, and J. Vearncombe. "Drill core, structure and digital technologies." Applied Earth Science 123, no. 1 (March 2014): 47–68. http://dx.doi.org/10.1179/1743275814y.0000000051.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Love, Serena. "The Abusir Drill Core Survey, Egypt." Papers from the Institute of Archaeology 12 (November 15, 2001): 110. http://dx.doi.org/10.5334/pia.158.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Kozhevnikov, A. "Tungsten Carbide Core Drill Bit STK." Nauka ta innovacii 2, no. 3 (May 30, 2006): 98–100. http://dx.doi.org/10.15407/scin2.03.098.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Fu, Yu Kun, Chuan Jun Han, Juan Wang, and Yang Yi. "Design and Analysis of Rubber Core with PTFE Ring in Ram BOP." Applied Mechanics and Materials 155-156 (February 2012): 686–90. http://dx.doi.org/10.4028/www.scientific.net/amm.155-156.686.

Full text

Abstract:

In order to enhance the sealing performance of rubber core in ram blowout preventer, this paper designed a new structure of the rubber core which embedded a half-PTFE ring in the central of rubber core based on the characteristics of failure mode on the contact surface. Through carrying out the experiment on the rubber under different temperature and pressure to determine the constitutive relation of the rubber core, this paper has established the 3D model of rubber core and drill pipe, accomplished the contact finite element analysis under 20MPa and compared with the general rubber core. The results show that in the contact surface between the new rubber core and the drill pipe, the whole rubber core is in stress concentration area, and the contact stress is bigger than the values of normal core with the drill pipe. When the well blowout occurred, it will have a greater sealing pressure between the PTFE ring and the drill pipe, which plays a greater role in blowout control. For the small friction coefficient between PTFE ring and drill pipe, the scuffing is reduced from the drill pipe and the service life of rubber core is extende

APA, Harvard, Vancouver, ISO, and other styles

20

Zagorodnov, V., and L. G. Thompson. "Thermal electric ice-core drills: history and new design options for intermediate-depth drilling." Annals of Glaciology 55, no. 68 (2014): 322–30. http://dx.doi.org/10.3189/2014aog68a012.

Full text

Abstract:

AbstractIce coring of temperate and polythermal glaciers demonstrates some limitations of most electromechanical (EM) and thermal electric (TE) drills. Most TE drills are heavy, require a heavy power system, work slowly and cannot operate in boreholes going through the cold–temperate ice transition. Antifreeze thermal electric drills (ATED) are capable of operating in polar ice caps, polythermal and temperate glaciers, in boreholes filled with water and/or hydrophilic fluids. Performance of the ATED drill can be improved by using an open-top core barrel and low-power and narrow-kerf coring head. ATED-type drills can be modified for an open-top core barrel equipped with low-power coring head and include a new scheme for drilling-fluid circulation using two pumps. A small metering pump releases pure ethanol above the top of the drill, and a second pump enables circulation of the borehole fluid, an ethanol–water solution (EWS), above the kerf. Use of a narrow-kerf coring head reduces power requirements and makes it possible to design a lightweight drilling system that includes the EM and TE drills for shallow and intermediate-depth drilling.

APA, Harvard, Vancouver, ISO, and other styles

21

Augustin, L., H. Motoyama, F. Wilhelms, S. Johnsen, S. B. Hansen, P. Talalay, and N. Vasiliev. "Drilling comparison in ‘warm ice’ and drill design comparison." Annals of Glaciology 47 (2007): 73–78. http://dx.doi.org/10.3189/172756407786857820.

Full text

Abstract:

AbstractFor the deep ice-core drilling community, the 2005/06 Antarctic season was an exciting and fruitful one. In three different Antarctic locations, Dome Fuji, EPICA DML and Vostok, deep drillings approached bedrock (the ice–water interface in the case of Vostok), emulating what had previously been achieved at NorthGRIP, Greenland, (summer 2003 and 2004) and at EPICA Dome C2, Antarctica (season 2004/05). For the first time in ice-core drilling history, three different types of drill (KEMS, JARE and EPICA) simultaneously reached the depth of ‘warm ice’ under high pressure. After excellent progress at each site, the drilling rate dropped and the drilling teams had to deal with refrozen ice on cutters and drill heads. Drills have different limits and perform differently. In this comparative study, we examine depth, pressure, temperature, pump flow and cutting speed. Finally, we compare a few parameters of ten different deep drills.

APA, Harvard, Vancouver, ISO, and other styles

22

HU, ZHENGYI, PAVEL TALALAY, ZHICHUAN ZHENG, PINLU CAO, GUITAO SHI, YUANSHENG LI, XIAOPENG FAN, and HONGMEI MA. "Air reverse circulation at the hole bottom in ice-core drilling." Journal of Glaciology 65, no. 249 (January 24, 2019): 149–56. http://dx.doi.org/10.1017/jog.2018.95.

Full text

Abstract:

ABSTRACTIce-core drilling to depths of 200–300 m is an important part of research studies concerned with paleoclimate reconstruction and anthropogenic climate change. However, conventional drilling methods face difficulties due to firn permeability. We have developed an electromechanical ice-core drill with air reverse circulation at the hole bottom. We believe that the new drilling system will recover ice cores faster than shallow auger drills, with high efficiency and low energy consumption. The theoretically estimated up-hole speed of the airflow should be not <7.7 m s−1 to allow proper removal of ice cuttings from the borehole bottom. The computer simulation and test results showed that the design of the new ice-coring drill is feasible. The maximum allowed penetration rate depends by square law on airflow.

APA, Harvard, Vancouver, ISO, and other styles

23

Nguyen, Dong Truong, and Chris Clarkson. "THE ORGANISATION OF DRILL PRODUCTION AT A NEOLITHIC LITHIC WORKSHOP SITE OF BAI BEN, CAT BA ISLAND, VIETNAM." Bulletin of the Indo-Pacific Prehistory Association 33 (November 14, 2014): 24. http://dx.doi.org/10.7152/bippa.v33i0.14508.

Full text

Abstract:

We investigate stone drill point production, use, maintenance, and discard from a technological perspective at the Late Neolithic workshop of Bai Ben on Cat Ba Island, Northeastern Vietnam. Bai Ben contains over 18,000 retouched chert flakes classified as drill points and dating to c.3000BP. Large scale production of drills most likely took place for reasons of mass production of drilled organic and inorganic objects. Few of such drilled objects are found at the site, perhaps due to poor organic preservation or removal of finished objects for trade and exchange. An analysis of attribute on drills and cores examines the time-ordering of dimensional and morphological changes as reduction continued at the site. The research finds that drills were produced from a diverse range of nodules sizes, blanks, core technologies and raw materials, but similar blanks were selected to produce very similar drill point forms.

APA, Harvard, Vancouver, ISO, and other styles

24

Warming, E., A. Svensson, P. Vallelonga, and M. Bigler. "A technique for continuous detection of drill liquid in ice cores." Journal of Glaciology 59, no. 215 (2013): 503–6. http://dx.doi.org/10.3189/2013jog12j124.

Full text

Abstract:

AbstractWhen drilling ice cores deeper than ∼100 m, drill liquid is required to maintain ice-core quality and to limit borehole closure. Due to high-pressure air bubbles in the ice, the ice core can crack during drilling and core retrieval, typically at 600–1200 m depth in Greenland. Ice from this ‘brittle zone’ can be contaminated by drill liquid as it seeps through cracks into the core. Continuous flow analysis (CFA) systems are routinely used to analyse ice for chemical impurities, so the detection of drill liquid is important for validating accurate measurements and avoiding potential instrument damage. An optical detector was constructed to identify drill liquid in CFA tubing by ultraviolet absorption spectroscopy at a wavelength of 290 nm. The set-up was successfully field-tested in the frame of the NEEM ice-core drilling project in Greenland. A total of 27 cases of drill liquid contamination were identified during the analysis of 175 m of brittle zone ice. The analyses most strongly affected by drill liquid contamination include insoluble dust particles, electrolytic conductivity, ammonium, hydrogen peroxide and sulphate. This method may also be applied to other types of drill liquid used at other drill sites.

APA, Harvard, Vancouver, ISO, and other styles

25

Blake, Erik W., Cameron P. Wake, and Michael D. Gerasimoff. "The Eclipse drill: A field-portable intermediate-depth ice-coring drill." Journal of Glaciology 44, no. 146 (1998): 175–78. http://dx.doi.org/10.3189/s0022143000002471.

Full text

Abstract:

AbstractA derivative of the Danish tipping-lower intermediate-depth ice-coring drill system has been developed for use in remote areas. The system as described is capable of drilling to depths of 250 m, although the drill has been proven to 350 m. The drill system is designed to be transported by hand and consumes 700 W maximum power from a 24 V Ac. battery bank charged by solar panels or a small generator. A field test in the St Elias Mountains, Yukon, produced good-quality core to 161.6 m depth; drilling at 6500 m a.s.l. on Far East Rongbuk Glacier, Mount Everest, produced good core to 42 m depth.

APA, Harvard, Vancouver, ISO, and other styles

26

Blake, Erik W., Cameron P. Wake, and Michael D. Gerasimoff. "The Eclipse drill: A field-portable intermediate-depth ice-coring drill." Journal of Glaciology 44, no. 146 (1998): 175–78. http://dx.doi.org/10.1017/s0022143000002471.

Full text

Abstract:

AbstractA derivative of the Danish tipping-lower intermediate-depth ice-coring drill system has been developed for use in remote areas. The system as described is capable of drilling to depths of 250 m, although the drill has been proven to 350 m. The drill system is designed to be transported by hand and consumes 700 W maximum power from a 24 V Ac. battery bank charged by solar panels or a small generator. A field test in the St Elias Mountains, Yukon, produced good-quality core to 161.6 m depth; drilling at 6500 m a.s.l. on Far East Rongbuk Glacier, Mount Everest, produced good core to 42 m depth.

APA, Harvard, Vancouver, ISO, and other styles

27

Sjöqvist, A. S. L., M. Arthursson, A. Lundström, E. Calderón Estrada, A. Inerfeldt, and H. Lorenz. "An innovative optical and chemical drill core scanner." Scientific Drilling 19 (May 29, 2015): 13–16. http://dx.doi.org/10.5194/sd-19-13-2015.

Full text

Abstract:

Abstract. We describe a new innovative drill core scanner that semi-automatedly analyses drill cores directly in drill core trays with X-ray fluorescence spectrometry, without the need for much sample preparation or operator intervention. The instrument is fed with entire core trays, which are photographed at high resolution and scanned by a 3-D profiling laser. Algorithms recognise the geometry of the core tray, number of slots, location of the drill cores, calculate the optimal scanning path, and execute a continuous XRF analysis of 2 cm width along the core. The instrument is equipped with critical analytical components that allow an effective QA/QC routine to be implemented. It is a mobile instrument that can be manoeuvred by a single person with a manual pallet jack.

APA, Harvard, Vancouver, ISO, and other styles

28

Betlem, Peter, Thomas Birchall, Kei Ogata, Joonsang Park, Elin Skurtveit, and Kim Senger. "Digital Drill Core Models: Structure-from-Motion as a Tool for the Characterisation, Orientation, and Digital Archiving of Drill Core Samples." Remote Sensing 12, no. 2 (January 19, 2020): 330. http://dx.doi.org/10.3390/rs12020330.

Full text

Abstract:

Structure-from-motion (SfM) photogrammetry enables the cost-effective digital characterisation of seismic- to sub-decimetre-scale geoscientific samples. The technique is commonly used for the characterisation of outcrops, fracture mapping, and increasingly so for the quantification of deformation during geotechnical stress tests. We here apply SfM photogrammetry using off-the-shelf components and software, to generate 25 digital drill core models of drill cores. The selected samples originate from the Longyearbyen CO2 Lab project’s borehole DH4, covering the lowermost cap rock and uppermost reservoir sequences proposed for CO2 sequestration onshore Svalbard. We have come up with a procedure that enables the determination of bulk volumes and densities with precisions and accuracies similar to those of such conventional methods as the immersion in fluid method. We use 3D printed replicas to qualitatively assure the volumes, and show that, with a mean deviation (based on eight samples) of 0.059% compared to proven geotechnical methods, the photogrammetric output is found to be equivalent. We furthermore splice together broken and fragmented core pieces to reconstruct larger core intervals. We unwrap these to generate and characterise 2D orthographic projections of the core edge using analytical workflows developed for the structure-sedimentological characterisation of virtual outcrop models. Drill core orthoprojections can be treated as directly correlatable to optical borehole-wall imagery data, enabling a direct and cost-effective elucidation of in situ drill core orientation and depth, as long as any form of borehole imagery is available. Digital drill core models are thus complementary to existing physical and photographic sample archives, and we foresee that the presented workflow can be adopted for the digitisation and digital storage of other types of geological samples, including degradable and dangerous ice and sediment cores and samples.

APA, Harvard, Vancouver, ISO, and other styles

29

RIX, JULIUS, ROBERT MULVANEY, JIALIN HONG, and DAN ASHURST. "Development of the British Antarctic Survey Rapid Access Isotope Drill." Journal of Glaciology 65, no. 250 (March 7, 2019): 288–98. http://dx.doi.org/10.1017/jog.2019.9.

Full text

Abstract:

ABSTRACTThe British Antarctic Survey Rapid Access Isotope Drill is an innovative new class of electromechanical ice drill, which has recently been used to drill the deepest dry hole drilled by an electromechanical auger drill. The record-breaking depth of 461.58 m was drilled in just over 104 hours at Little Dome C. The drill collects ice chippings, for water stable isotope analysis, rather than an ice core. By not collecting a core the winch can be geared for speed rather than core breaking and is lightweight. Furthermore, emptying of the chippings is performed by simply reversing the drill motor on the surface reducing the overall drilling time significantly. The borehole is then available for instrumentation. We describe the drill in its current state including modifications carried out since it was last deployed. Test seasons and the lessons learned from each are outlined. Finally, future developments for this class of drill are discussed.

APA, Harvard, Vancouver, ISO, and other styles

30

Wang, Tao. "Stuck-Point Calculation for Exploration Core Drilling with Application of Full-Hydraulic Drill Rig." Advanced Materials Research 619 (December 2012): 355–60. http://dx.doi.org/10.4028/www.scientific.net/amr.619.355.

Full text

Abstract:

Stuck-point calculation (SPC) is an important method to determine the stuck position of the drill string. It is of practical significance to explore and promote the SPC application in the field of mineral exploration. While Hooke's law is the foundation for the mathematical modeling, drill site conditions such as ground formation, borehole design and drilling process will be defining the factors and parameters in the formula. In recent years, the use of advanced full-hydraulic core drills provides a convenient means of on-site operation for stuck-point calculation. In this paper, the experimental operation at a deep-hole complex-formation drilling project in Yunnan Province, Southwest China, verifies that the SPC method is effective and conductive for mineral exploration core drilling activities.

APA, Harvard, Vancouver, ISO, and other styles

31

Amini, Saeid, Mohammad Baraheni, and Alireza Mardiha. "Parametric investigation of rotary ultrasonic drilling of carbon fiber reinforced plastics." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 232, no. 5 (August 23, 2017): 540–54. http://dx.doi.org/10.1177/0954408917727199.

Full text

Abstract:

Carbon fiber reinforced plastics are used in various industrial applications for their excellent properties. Rotary ultrasonic drilling is the new machining process used to drill holes on fiber-reinforced plastics and has been attracting increased attention in recent years. Dimensional tolerances are very important in machining of carbon fiber reinforced plastics. Additionally, diamond core drills are simultaneously drilling and grinding fiber reinforced plastics. This paper aims to investigate thrust force and dimensional tolerances including roundness and cylindricity in rotary ultrasonic drilling of carbon fiber reinforced plastics using diamond core drill. To this end, a proper ultrasonic system for a core drill in ABAQUS is designed and fabricated. Thrust force in rotary ultrasonic drilling when compared to conventional drilling reduced by up to 30%. Besides, roundness and cylindricity decreased by up to 80% and 72%, respectively. Afterwards, analysis of variance demonstrated that vibration is more influential than other machining parameters in order to improve the hole accuracy. That is, obtained exponential regression models predict roundness and cylindricity through machining parameters with high accuracy. Feed rate of 30 mm/min and spindle speed of 1400 r/min by exerting vibration on the tool is considered to be the optimized condition.

APA, Harvard, Vancouver, ISO, and other styles

32

Cao, Pinlu, Qi Zhao, Zhuo Chen, Hongyu Cao, and Baoyi Chen. "Orthogonal experimental research on the structural parameters of a novel drill bit used for ice core drilling with air reverse circulation." Journal of Glaciology 65, no. 254 (October 22, 2019): 1011–22. http://dx.doi.org/10.1017/jog.2019.76.

Full text

Abstract:

AbstractA new type of ice core drill bit, designed with a vane swirler, was developed for ice core drilling with air reverse circulation. An orthogonal experimental design method was employed to investigate the effects of the swirler structure parameters on the reverse circulation performance of the drill bit including helical angle, number of blades, blade length and blade central angle, etc. The entrainment ratio was used to evaluate the reverse circulation effectiveness of the drill bit. The results show that the helical angle is the dominant factor regardless of whether or not the flushing nozzles are part of the design of the drill bit. The number of blades is the least important factor for the drill bit designed with the flushing nozzles (referred to as drill bit I), while the outlet area of the swirling slot is the least influential factor for the drill bit without flushing nozzles (referred to as drill bit П). In addition, the appearance of the ice core has a certain effect on the air reverse circulation for both drill bits. Within the ranges of this study, the optimal structure of the drill bit was determined based on the range analysis of the orthogonal design.

APA, Harvard, Vancouver, ISO, and other styles

33

Johnsen, Sigfús J., Steffen Bo Hansen, Simon G. Sheldon, Dorthe Dahl-Jensen, Jørgen P. Steffensen, Laurent Augustin, Paul Journé, et al. "The Hans Tausen drill: design, performance, further developments and some lessons learned." Annals of Glaciology 47 (2007): 89–98. http://dx.doi.org/10.3189/172756407786857686.

Full text

Abstract:

AbstractIn the mid-1990s, excellent results from the GRIP and GISP2 deep drilling projects in Greenland opened up funding for continued ice-coring efforts in Antarctica (EPICA) and Greenland (NorthGRIP). The Glaciology Group of the Niels Bohr Institute, University of Copenhagen, was assigned the task of providing drilling capability for these projects, as it had done for the GRIP project. The group decided to further simplify existing deep drill designs for better reliability and ease of handling. The drill design decided upon was successfully tested on Hans Tausen Ice Cap, Peary Land, Greenland, in 1995. The 5.0m long Hans Tausen (HT) drill was a prototype for the ~11m long EPICA and NorthGRIP versions of the drill which were mechanically identical to the HT drill except for a much longer core barrel and chips chamber. These drills could deliver up to 4m long ice cores after some design improvements had been introduced. The Berkner Island (Antarctica) drill is also an extended HT drill capable of drilling 2 m long cores. The success of the mechanical design of the HT drill is manifested by over 12 km of good-quality ice cores drilled by the HT drill and its derivatives since 1995.

APA, Harvard, Vancouver, ISO, and other styles

34

Scott, Robert J., and David Selley. "Measurement of fold axes in drill core." Journal of Structural Geology 26, no. 4 (April 2004): 637–42. http://dx.doi.org/10.1016/j.jsg.2003.08.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Jing, Yapeng, Haitao Su, Shao Wang, Wenhua Gui, and Qing Guo. "Fault Diagnosis of Electric Impact Drills Based on Time-Varying Loudness and Logistic Regression." Shock and Vibration 2021 (March 23, 2021): 1–11. http://dx.doi.org/10.1155/2021/6655090.

Full text

Abstract:

As the main component of an electric impact drill, the gearbox is used to decelerate and transmit power; damage and failure to the gears often lead to the transmission system's failure. Therefore, as the core component of power transmission, the fault detection and diagnosis of gearbox devices have attracted increasing attention. This paper presents a psychoacoustic-based fault diagnosis method for gears of electric impact drills. The proposed methods employ acoustic signals and the time-varying loudness theory of psychoacoustic parameters. Two states of electric impact drills were analyzed: an electric impact drill with healthy gears and an electric impact drill with faulty gears. A feature extraction peak-to-average ratio (PAR) method based on the time-varying loudness spectrum was described and implemented to compute the feature vectors. The classification was carried out by applying logistic regression (LR). This paper provides the results of an acoustic analysis of electric impact drills. The results had a good recognition rate and the total accuracy of recognition of EIDs based on the PAR with LR was 97%. This method simulates the human auditory perception to detect the gear components of an electric impact drill, which can replace the traditional artificial listening detection method.

APA, Harvard, Vancouver, ISO, and other styles

36

Su, Hong Hua, Hong Jun Xu, Bing Xiao, Yu Can Fu, and Jiu Hua Xu. "Study on Machining of Hard-Brittle Materials with Thin-Walled Monolayer Brazed Diamond Core Drill." Materials Science Forum 471-472 (December 2004): 287–91. http://dx.doi.org/10.4028/www.scientific.net/msf.471-472.287.

Full text

Abstract:

A new method for fabricating the thin-walled diamond core drill by brazing technology and the optimum grain distribution was proposed in this paper. Machining performance experiments have been carried out, including contrast tests about drill life and machining efficiency for the thin- walled monolayer brazed diamond core drill and electroplated one. The testing results show that thin-walled monolayer brazed diamond core drill has certainly super-excellent machining performance. Wear mechanism of diamond grits was studied in tho se drilling processes. No pulling out for the thin-walled monolayer brazed diamond core drill grits is the key factor of its longer life, and the optimum grain distribution and less wear flat of grits during drilling decrease the drilling spindle direction force, and improve the machining efficiency. It can be concluded that the new technology can radically improve the bonding strength at the grains interface, and make every grain effective during drilling.

APA, Harvard, Vancouver, ISO, and other styles

37

Harraden, Cassady L., Matthew J. Cracknell, James Lett, Ron F. Berry, Ronell Carey, and Anthony C. Harris. "Automated Core Logging Technology for Geotechnical Assessment: A Study on Core from the Cadia East Porphyry Deposit." Economic Geology 114, no. 8 (December 1, 2019): 1495–511. http://dx.doi.org/10.5382/econgeo.4649.

Full text

Abstract:

Abstract The Cadia East porphyry deposit, located approximately 20 km south of Orange, New South Wales, Australia, contains a significant resource of copper and gold. This resource is hosted within the Forest Reefs Volcanics and is spatially and temporally associated with the Cadia Intrusive Complex. To extract ore, the underground mine currently uses the block cave mining method. The Cadia East geotechnical model provides data inputs into a range of numerical and empirical analysis methods that make up the foundation for mine design. These data provide input into the construction of stress models, caveability models, ground support design, and fragmentation analysis. This geotechnical model encompasses two commonly used rock classification systems that quantify ground conditions: (1) rock mass rating (RMR) and (2) rock tunneling quality index (Q index). The RMR and Q index are calculated from estimates of rock quality designation (RQD), number of fracture sets, fracture roughness, fracture alteration, and fracture spacing. Geologists and geotechnical engineers collect information used to produce these estimates by manually logging sections of drill core, a time-consuming task that can result in inconsistent data. Modern automated core scanning technologies offer opportunities to rapidly collect data from larger samples of drill core. These automated core logging systems generate large volumes of spatially and spectrally consistent data, including a model of the drill core surface from a laser profiling system. Core surface models are used to extract detailed measurements of fracture location, orientation, and roughness from oriented drill core. These data are combined with other morphological and mineralogical outputs from automated hyperspectral core logging systems to estimate RMR and the Q index systematically over contiguous drill core intervals. The goal of this study was to develop a proof-of-concept methodology that extracts geotechnical index parameters from hyperspectral and laser topographic data collected from oriented drill core. Hyperspectral data from the Cadia East mine were used in this case study to assess the methods. The results show that both morphological and mineralogical parameters that contribute to the RMR and Q index can be extracted from the automated core logging data. This approach provides an opportunity to capture consistent geologic, mineralogical, and geotechnical data at a scale that is too time-consuming to achieve via manual data collection.

APA, Harvard, Vancouver, ISO, and other styles

38

Triest, Jack, Robert Mulvaney, and Olivier Alemany. "Technical innovations and optimizations for intermediate ice-core drilling operations." Annals of Glaciology 55, no. 68 (2014): 243–52. http://dx.doi.org/10.3189/2014aog68a049.

Full text

Abstract:

AbstractThe British Antarctic Survey, in collaboration with Laboratoire de Glaciologie et Géophysique de l’Environnement, has in recent years successfully drilled to bedrock on three remote sites around the Antarctic Peninsula. Based on the experience from the multi-season project at Berkner Island (948m depth, 2002–05) we optimized the drill set-up to better suit two subsequent single-season projects at James Ross Island (363m depth, 2008) and Fletcher Promontory (654m depth, 2012). The adaptations, as well as the reasons for them, are discussed in detail and include a drill tent set-up without a trench; drilling without a borehole casing with a relatively low fluid column height; and using a shorter drill. These optimizations were aimed at reducing cargo loads and installation time while maintaining good core quality, productivity and a safe working environment. In addition, we introduce a number of innovations, ranging from a new lightweight cable tensioning device and drill-head design to core storage and protection trays. To minimize the environmental impact, all the drill fluid was successfully recovered at both sites and we describe and evaluate this operation.

APA, Harvard, Vancouver, ISO, and other styles

39

Engelhardt, H., B. Kamb, and R. Bolsey. "A hot-water ice-coring drill." Journal of Glaciology 46, no. 153 (2000): 341–45. http://dx.doi.org/10.3189/172756500781832873.

Full text

Abstract:

AbstractA new method of ice-core drilling uses an annulus of hot-water jets to melt out a cylindrical ice core. This lightweight device used in combination with a fast hot-water drill can quickly obtain ice cores from any depth.

APA, Harvard, Vancouver, ISO, and other styles

40

Slawny, Kristina R., Jay A. Johnson, Nicolai B. Mortensen, Christopher J. Gibson, Joshua J. Goetz, Alexander J. Shturmakov, Donald A. Lebar, and Anthony W. Wendricks. "Production drilling at WAIS Divide." Annals of Glaciology 55, no. 68 (2014): 147–55. http://dx.doi.org/10.3189/2014aog68a018.

Full text

Abstract:

AbstractThe deep ice-sheet coring (DISC) drill was used for production ice-core drilling at WAIS Divide in Antarctica for six field seasons between 2007 and 2013. Continuous ice-core samples were obtained between the snow surface and 3405 m depth. During the 2012/13 austral summer, the DISC drill’s newly designed replicate ice-coring system was utilized to collect nearly 285m of additional high-quality core samples at depths of high scientific interest. Annual progress graphs are described, as well as milestones achieved over the course of the project. Drilling operations, challenges encountered, drill fluid usage, drilling results, and the drill crew’s experiences with the DISC drill and replicate coring system during production drilling are described and discussed in detail. Core-processing operations are described briefly, as well as the logistical undertaking of the DISC drill’s deployment to Antarctica.

APA, Harvard, Vancouver, ISO, and other styles

41

Proborukmi, Maria Sekar, Brigitte Urban, Manfred Frechen, Alf Grube, and Christian Rolf. "Late Pliocene–Pleistocene record of the Garding-2 research drill core, Northwest Germany." Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 168, no. 1 (March 1, 2017): 141–67. http://dx.doi.org/10.1127/zdgg/2017/0103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Lewis A., Buitrago Gomez, Stefan Miska, and Małgorzata Ziaja. "Experimental study of layouts of PDC cutters in core bit drilling." AGH Drilling, Oil, Gas 33, no. 2 (2016): 341. http://dx.doi.org/10.7494/drill.2016.33.2.341.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

TAKAHASHI, Akiyoshi. "Development of a new shallow ice core drill." Journal of the Japanese Society of Snow and Ice 58, no. 1 (1996): 29–37. http://dx.doi.org/10.5331/seppyo.58.29.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Mwanga, Abdul, Pertti Lamberg, and Jan Rosenkranz. "Comminution test method using small drill core samples." Minerals Engineering 72 (March 2015): 129–39. http://dx.doi.org/10.1016/j.mineng.2014.12.009.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Seaman, Caroline, Sarah Bean Sherman, Michael O. Garcia, Michael B. Baker, Brian Balta, and Edward Stolper. "Volatiles in glasses from the HSDP2 drill core." Geochemistry, Geophysics, Geosystems 5, no. 9 (September 2004): n/a. http://dx.doi.org/10.1029/2003gc000596.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Kunzendorf, H., R. Gwozdz, H. J. Hansen, and N. Svendsen. "Trace elements in a North Sea drill core." Applied Geochemistry 1, no. 3 (May 1986): 383–94. http://dx.doi.org/10.1016/0883-2927(86)90023-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Tsao, C. C., and H. Hocheng. "Parametric study on thrust force of core drill." Journal of Materials Processing Technology 192-193 (October 2007): 37–40. http://dx.doi.org/10.1016/j.jmatprotec.2007.04.062.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Contreras Acosta, Isabel Cecilia, Mahdi Khodadadzadeh, and Richard Gloaguen. "Resolution Enhancement for Drill-Core Hyperspectral Mineral Mapping." Remote Sensing 13, no. 12 (June 11, 2021): 2296. http://dx.doi.org/10.3390/rs13122296.

Full text

Abstract:

Drill-core samples are a key component in mineral exploration campaigns, and their rapid and objective analysis is becoming increasingly important. Hyperspectral imaging of drill-cores is a non-destructive technique that allows for non-invasive and fast mapping of mineral phases and alteration patterns. The use of adapted machine learning techniques such as supervised learning algorithms allows for a robust and accurate analysis of drill-core hyperspectral data. One of the remaining challenge is the spatial sampling of hyperspectral sensors in operational conditions, which does not allow us to render the textural and mineral diversity that is required to map minerals with low abundances and fine structures such as veins and faults. In this work, we propose a methodology in which we implement a resolution enhancement technique, a coupled non-negative matrix factorization, using hyperspectral, RGB images and high-resolution mineralogical data to produce mineral maps at higher spatial resolutions and to improve the mapping of minerals. The results demonstrate that the enhanced maps not only provide better details in the alteration patterns such as veins but also allow for mapping minerals that were previously hidden in the hyperspectral data due to its low spatial sampling.

APA, Harvard, Vancouver, ISO, and other styles

49

Orpen, John, and David Orpen. "Error-Proofing Diamond Drilling and Drill Core Measurements." SEG Discovery, no. 123 (October 1, 2020): 23–34. http://dx.doi.org/10.5382/geo-and-mining-09.

Full text

Abstract:

Editor’s note: The Geology and Mining series, edited by Dan Wood and Jeffrey Hedenquist, is designed to introduce early-career professionals and students to a variety of topics in mineral exploration, development, and mining, in order to provide insight into the many ways in which geoscientists contribute to the mineral industry. Abstract The diamond drill is the most productive tool available for the earth scientist to explore and map the subsurface. However, the quality of the information obtained for analysis and modeling depends on how well the processes involved are understood so as to eliminate systematic and human error and effectively minimize the variables causing random error. This overview of the quality assurance and quality control (QA/QC) procedures required to manage these errors starts with the planning phase of a drilling program and goes through drill rig setup, borehole depth measurement, core recovery measurement, core depth registration, core orientation, borehole survey, and borehole path reconstruction. An outline follows of the methods used in the logging process to accurately depth reference the data recorded from both core and bore, as well as to ensure that the angles measured for structures are verified and correctly rotated to derive their in situ dip and dip direction or plunge and trend. To conclude, the provisions required for effective audits of the drilling and logging QA/QC processes are discussed: testing for inconsistencies, certifying that standards have been achieved, reporting on weaknesses, and making recommendations for improved performance.

APA, Harvard, Vancouver, ISO, and other styles

50

Saoudi, Jamel, Redouane Zitoune, Suhasini Gururaja, Mehdi Salem, and Salah Mezleni. "Analytical and experimental investigation of the delamination during drilling of composite structures with core drill made of diamond grits: X-ray tomography analysis." Journal of Composite Materials 52, no. 10 (August 10, 2017): 1281–94. http://dx.doi.org/10.1177/0021998317724591.

Full text

Abstract:

Among the various forms of material damage, exit-ply delamination has been identified as one of the most deleterious damage processes associated with drilling fibre-reinforced plastics. The thrust force has been cited as the primary cause for drilling-induced exit-ply delamination. Only one analytical model for the prediction of the critical thrust force responsible for delamination using core drills can be found in the literature. In this study, a realistic model to predict critical thrust force responsible for drilling-induced exit-ply delamination in a multi-directional carbon fibre-reinforced plastic laminate with core drill has been proposed. A comparison between the proposed model, literature model as well as the experimental tests conducted during punching tests is presented. The proposed model is found to correlate well with experimental punching tests. In fact, the maximum relative errors recorded between the experimental values of the critical thrust force and the measured values are around 15%. Micro-tomography experiments have also been conducted that capture the drilling-induced damage in multi-directional carbon fibre-reinforced plastics in great detail. The X-ray images highlight the difficulty in controlling the thickness of the uncut plies located under the core drill during punching tests that can be attributed to some deviations in predictions of critical thrust force. Postmortem examination of the blind holes after punching tests also confirms the presence of a net delamination near the vicinity of the nominal diameter of the core drill, which correlates well to the hypothesis of the analytical model.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Drill core'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles