Editorial

3 pages, 177 KiB

Open AccessEditorial

Editorial for Special Issue “Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining”

by Shiki Machida and Kentaro Nakamura

Minerals 2022, 12(6), 686; https://0-doi-org.brum.beds.ac.uk/10.3390/min12060686 - 29 May 2022

Viewed by 1257

Abstract

The development of deep-sea ferromanganese nodules has the potential to provide critical metals for the creation of high-tech and green-tech technologies and devices [...] Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

Research

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16 pages, 5922 KiB

Open AccessArticle

First Demonstration of Recognition of Manganese Crust by Deep-Learning Networks with a Parametric Acoustic Probe

by Feng Hong, Minyan Huang, Haihong Feng, Chengwei Liu, Yong Yang, Bo Hu, Dewei Li and Wentao Fu

Minerals 2022, 12(2), 249; https://0-doi-org.brum.beds.ac.uk/10.3390/min12020249 - 16 Feb 2022

Cited by 4 | Viewed by 2254

Abstract

The quantitative evaluations of mineral resources and delineation of promising areas in survey regions for future mining have attracted many researchers’ interest. Cobalt-Rich manganese crusts (Mn-crusts), as one of the three significant strategic submarine mineral resources, lack effective and low-cost detection devices for [...] Read more.

The quantitative evaluations of mineral resources and delineation of promising areas in survey regions for future mining have attracted many researchers’ interest. Cobalt-Rich manganese crusts (Mn-crusts), as one of the three significant strategic submarine mineral resources, lack effective and low-cost detection devices for surveying since the challenging distribution requires a high vertical and horizontal resolution. To solve this problem, we have built an engineering prototype parametric acoustic probe named PPPAAP19. With the echo data acquired by the probe, the interpretation of the accurate thickness information and the seabed classification using the deep learning network-based method are realized. We introduce the acoustic dataset of the minerals collected from two sea trials. Firstly, the preprocessing method and data augment strategy used to form the dataset are described. Afterward, the performances of several baseline approaches are assessed on the dataset, and the experimental results show that they all achieve high accuracy for binary classification. We find that the end-to-end approach for binary classification based on a 1D Convolution Neural Network has a comprehensive advantage. Such a demonstration validates the possibility of binary classification for recognizing the ferromanganese crust only in an acoustic manner, which may significantly contribute to the efficiency of the survey. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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17 pages, 5650 KiB

Open AccessFeature PaperArticle

Intermittent Beginning to the Formation of Hydrogenous Ferromanganese Nodules in the Vast Field: Insights from Multi-Element Chemostratigraphy Using Microfocus X-ray Fluorescence

by Shiki Machida, Ryo Shimomura, Kentaro Nakamura, Tetsu Kogiso and Yasuhiro Kato

Minerals 2021, 11(11), 1246; https://0-doi-org.brum.beds.ac.uk/10.3390/min11111246 - 10 Nov 2021

Cited by 3 | Viewed by 1841

Abstract

Vast ferromanganese nodule fields have been found on the deep-sea floor of all oceans worldwide. They have received attention because they potentially provide high-grade metal resources to develop future high- and green-technology. However, how these vast nodule fields were formed and developed owing [...] Read more.

Vast ferromanganese nodule fields have been found on the deep-sea floor of all oceans worldwide. They have received attention because they potentially provide high-grade metal resources to develop future high- and green-technology. However, how these vast nodule fields were formed and developed owing to their widespread nature or tendency to be denser with an increasing number of nodules has not yet been established. In this study, the fine-scale inner structure of nodules of various sizes was analyzed on the basis of chemical mapping using microfocus X-ray fluorescence. We found that nodules distributed in the vast field around Minamitorishima (Marcus) Island have several types of innermost layers, which correspond to different chemostratigraphic layers of nodules that have been previously reported by us in this region. As nodules grow in order from the center to the outside, the different types in the innermost layer indicate a difference in the timing of the beginning of their growth. Moreover, because the differences in the chemical features of each layer reflect differences in the composition of the original deep-sea water, our results imply that the beginning of nodule formation occurred intermittently at each time of a water mass replacement due to new deep-sea currents flowing into this region. We recognized that the northern part of the study area was dominated by large nodules that started to grow in relatively earlier times, while the southern part tended to have many nodules that grew in relatively later times. Based on these observations, we hypothesize that the intermittent beginning of nodule formation is governed by the northward inflow of the deep-sea current that originated from the Lower Circumpolar Deep Water for an extended time to form the vast nodule field. Because patterns in the timing of nodule formation were different in the eastern and western regions, we thus further propose that the topographic framework, i.e., the arrangement of individual large seamounts and the cluster of small knolls and petit-spot volcanoes, strongly regulates the flow path of the deep-sea current, even if the position of the entire seamount changes owing to plate motion. The deep-sea current might supply some materials to be nuclei, resulting in the nodule formation at the beginning of the process. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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16 pages, 4472 KiB

Open AccessFeature PaperArticle

Three-Dimensional Structural Analysis of Ferromanganese Nodules from the Western North Pacific Ocean Using X-ray Computed Tomography

by Kentaro Nakamura, Daiki Terauchi, Ryo Shimomura, Shiki Machida, Kazutaka Yasukawa, Koichiro Fujinaga and Yasuhiro Kato

Minerals 2021, 11(10), 1100; https://0-doi-org.brum.beds.ac.uk/10.3390/min11101100 - 07 Oct 2021

Cited by 7 | Viewed by 1955

Abstract

The three-dimensional layered growth structure of 934 ferromanganese nodule samples collected from dives in the Pacific Ocean around Minamitorishima Island was assessed using X-ray computed tomography (X-ray CT) to elucidate their growth history. The thickness of the layered structure measured in three orthogonal [...] Read more.

The three-dimensional layered growth structure of 934 ferromanganese nodule samples collected from dives in the Pacific Ocean around Minamitorishima Island was assessed using X-ray computed tomography (X-ray CT) to elucidate their growth history. The thickness of the layered structure measured in three orthogonal directions showed that the ferromanganese nodules grew equally in all directions regardless of shape and size. Based on differences in CT numbers, a layered structure was subdivided into sublayers I, II, III, and IV, which corresponded to petrological features. The nodules were then classified as Types I, II, III, and IV according to whether they had sublayers I, I and II, I–III, or I–IV, respectively. Correlations between the total thickness of the layers and the number of sublayers indicated that both represented the relative age of the nodules. Nodules with all these types were recovered from most of the sampling sites, and histograms of the total layer thickness at each dive site showed several peaks. These findings indicated that the initiation of nodule growth was intermittent, rather than simultaneous. Three distinct thickness peaks were found at many sites throughout the study area, suggesting that at least three nodule initiation events covering hundreds of kilometers initiated the growth of ferromanganese nodules. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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22 pages, 11554 KiB

Open AccessArticle

Mineralogy and Geochemistry of Seabed Sediments of the Chiloé–Taitao Area, Southern Chile, and Implications for Ore Deposits

by Marisol Pérez, Marcelo García, Brian Townley and Katja Deckart

Minerals 2021, 11(8), 903; https://0-doi-org.brum.beds.ac.uk/10.3390/min11080903 - 21 Aug 2021

Cited by 1 | Viewed by 2979

Abstract

The oceanic seabed contains a variety of mineral resources related exclusively to submarine environments. Limited information has been documented for the seabed offshore of Chile, which is particularly interesting due to its geodynamic context and large area. Mineralogical and geochemical analyses of 16 [...] Read more.

The oceanic seabed contains a variety of mineral resources related exclusively to submarine environments. Limited information has been documented for the seabed offshore of Chile, which is particularly interesting due to its geodynamic context and large area. Mineralogical and geochemical analyses of 16 sites within the Chiloé–Taitao area, from 83 to 3388 m in depth, were carried out. The most abundant minerals are quartz, feldspars, pyroxenes, amphiboles, epidote, and biotite, with lower quantities of zircon, white mica, olivine, pyrite, magnetite, ilmenite, and hematite. Framboidal pyrites are mainly present at >900 m depth, and could be associated with methane hydrates, which have been reported in the area and its surroundings. Tenorite, sphalerite, tennantite, cordierite, birnessite, and tellurobismuthite were revealed by XRD analysis at low concentrations but at many sites. Birnessite, a Fe–Mn nodule-forming mineral, was widely detected, and Pearson correlations showed elemental associations related to the presence of Mn oxides. Samples did not evidence Fe–Mn nodules, probably due to the redox and depth conditions. Nonetheless, it is probable that to the west, polymetallic nodules are present in deeper zones. In the southern part of the area, reflective grains were identified, with up to 58.3 wt.% Cu; these grains might be derived from the continent or formed by in situ diagenetic precipitation. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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18 pages, 5449 KiB

Open AccessArticle

Degradation of Polymetallic Nodules in Deep-Sea Multi-Stage Lifting Motor Pump

by Yan Li, Kesen Liang, Huan Dai and Chi Zhang

Minerals 2021, 11(6), 656; https://0-doi-org.brum.beds.ac.uk/10.3390/min11060656 - 21 Jun 2021

Cited by 3 | Viewed by 2389

Abstract

The polymetallic nodules in the deep-sea multi-stage lifting motor pump will undergo repeated impeller blade impact and fragmentation, which will change the particle size, thereby affecting the number of ores that can be recovered on the surface and the design parameters of the [...] Read more.

The polymetallic nodules in the deep-sea multi-stage lifting motor pump will undergo repeated impeller blade impact and fragmentation, which will change the particle size, thereby affecting the number of ores that can be recovered on the surface and the design parameters of the processing equipment. A new calculation method of degradation rate is proposed. The degradation model of multiple impacts of particles is improved to quantitatively calculate the final particle size distribution (PSD) of polymetallic nodules transported from the Clarion Clipperton Zone (CCZ) to the ground through a series of multi-stage lifting electric pumps. The newly proposed calculation method is obtained by analyzing the degradation of experimental data of polymetallic nodules when they pass through the six-stage lifting motor pump experimental system many times. The improved model is used to predict the PSD of the nodules after running for 10 min in the experimental system, and compared with the experimental test results, the deviation is small. The new method can estimate the change in PSD of nodules due to degradation during transportation, reducing design costs for land processing equipment. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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15 pages, 1837 KiB

Open AccessArticle

Combined Mining and Pulp-Lifting of Ferromanganese Nodules and Rare-Earth Element-Rich Mud around Minamitorishima Island in the Western North Pacific: A Prefeasibility Study

by Tetsuo Yamazaki, Naoki Nakatani, Rei Arai, Tsunehiro Sekimoto and Hiroyuki Katayama

Minerals 2021, 11(3), 310; https://0-doi-org.brum.beds.ac.uk/10.3390/min11030310 - 17 Mar 2021

Cited by 7 | Viewed by 2445

Abstract

An examination of the technical and economic feasibility of the combined mining of the rare-earth element-rich mud (REE-rich mud) and ferromanganese nodules (FN) around Minamitorishima (Marcus) Island in Northwest Pacific is introduced. A previous study showed that the mining of REE-rich mud around [...] Read more.

An examination of the technical and economic feasibility of the combined mining of the rare-earth element-rich mud (REE-rich mud) and ferromanganese nodules (FN) around Minamitorishima (Marcus) Island in Northwest Pacific is introduced. A previous study showed that the mining of REE-rich mud around Minamitorishima Island was not economically feasible. Therefore, in this study, three changes from the previous mining model to improve its economy are proposed. The first one is combined mining with FN in the area. The second one is introducing a pulp-lifting system that can lift both REE-rich mud and FN at high concentrations through a riser pipe. The third one is the reuse of waste mud and processed slag for construction materials. The economic evaluation results show a change from a slightly negative to quite positive economy depending on the mixing ratio of REE-rich mud and FN in the pulp-lifting. In addition, some technical approaches necessary to realize the combined mining method are introduced. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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19 pages, 6277 KiB

Open AccessArticle

Stratigraphic Variations of Fe–Mn Micronodules and Implications for the Formation of Extremely REY-Rich Mud in the Western North Pacific Ocean

by Kazutaka Yasukawa, Satoshi Kino, Junichiro Ohta, Keishiro Azami, Erika Tanaka, Kazuhide Mimura, Koichiro Fujinaga, Kentaro Nakamura and Yasuhiro Kato

Minerals 2021, 11(3), 270; https://0-doi-org.brum.beds.ac.uk/10.3390/min11030270 - 06 Mar 2021

Cited by 11 | Viewed by 2091

Abstract

The origin of deep-sea sediments in the western North Pacific Ocean, which are significantly enriched in rare-earth elements and yttrium (REY), and its paleoceanographic implications have been poorly constrained. Here, we investigated stratigraphic variations in the chemical compositions and textures of ferromanganese (Fe–Mn) [...] Read more.

The origin of deep-sea sediments in the western North Pacific Ocean, which are significantly enriched in rare-earth elements and yttrium (REY), and its paleoceanographic implications have been poorly constrained. Here, we investigated stratigraphic variations in the chemical compositions and textures of ferromanganese (Fe–Mn) micronodules separated from western North Pacific sediments. The characteristics of the micronodules of an extremely REY-rich mud layer vary from almost purely diagenetic to relatively hydrogenetic. This indicates the abundant supply of organic matter to the sediment together with fish debris that accumulates REY at the onset of the REY-enrichment of the mud, followed by the exposure of the seafloor to oxic water masses during the latter half of the formation of the REY-rich mud. These results support a previously proposed formation mechanism based on which enhanced bottom water currents caused pelagic fish proliferation via the upwelling of nutrients and fish debris was physically sorted and selectively accumulated on the seafloor. After the main REY-enrichment, the micronodules exhibit varying diagenetic signatures, suggesting changes in the bottom current intensities after the main REY-enrichment. However, the bulk REY contents do not increase. This implies that a sufficient increase in the fish productivity is an essential factor affecting the formation of REY-rich mud. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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Review

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17 pages, 1963 KiB

Open AccessReview

The Development History and Latest Progress of Deep-Sea Polymetallic Nodule Mining Technology

by Yajuan Kang and Shaojun Liu

Minerals 2021, 11(10), 1132; https://0-doi-org.brum.beds.ac.uk/10.3390/min11101132 - 14 Oct 2021

Cited by 41 | Viewed by 10099

Abstract

Deep-sea polymetallic nodules are a mineral resource with potential for commercial development. Due to the unique deep-sea environment in which they are found, specialized technology and equipment are required for their extraction. In this paper, firstly, the development of deep-sea polymetallic nodule mining [...] Read more.

Deep-sea polymetallic nodules are a mineral resource with potential for commercial development. Due to the unique deep-sea environment in which they are found, specialized technology and equipment are required for their extraction. In this paper, firstly, the development of deep-sea polymetallic nodule mining technology is classified into three stages, and its characteristics are summarized. Moreover, the results from research into deep-sea polymetallic nodule mining technology are analyzed, including proposals for mining systems, research into key technologies, basic scientific problems, and proof of technical feasibility from sea tests. Secondly, the testing of the collector prototype and the environmental impact assessment study of Global Sea Mineral Resources NV, as well as the progress of the deep-sea polymetallic nodule mining test project in China, are introduced. On this basis, the opportunities and challenges brought by the fast-growing demand for electric vehicles to the development of deep-sea polymetallic mining technology is analyzed, and a possible technical scheme for a mining system and the trends in its development towards high reliability and high standards of environmental protection according to the requirements of commercial exploitation are explored. This provides a reference for the research and development of high-efficiency technology and equipment for the mining of deep-sea polymetallic nodules. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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