Scholarly record
THE ACCURACY OF POLYMETALLIC NODULE RESOURCES ESTIMATION IN THE PACIFIC IN THE IOM AREA BASED ON A SAMPLES COLLECTED USING A BOX CORER
Abstract
One of many factors determining the success of the future exploitation of oceanic polymetallic nodules is the amount of resources and the accuracy of their estimation. The potential exploitation requires accurate estimation of resources classified as measured resources according to the Australian JORC Code (The Joint Ore Reserves Committee Code). The issue of the accuracy of polymetallic nodule resources estimation was analyzed in the area of the Clarion-Clipperton Fracture Zone in the Pacific administered by the InterOceanMetal Joint Organization (IOM), the contractor of the International Seabed Authority (ISA) since 2001. The area of about 4 200 km2 selected for the analysis is one of the most prospective ones due to the abundance of nodules. The analysis was based on samples collected from the ocean floor using a box corer operated from the research ship. The average distance between sampling sites was about 8 km. The assessment of the accuracy of estimates was made for 15 square calculation blocks with a side of 17 km and an area of 300 km2. They roughly correspond to the areas of annual exploitation, assuming that the average abundance of wet nodules is 10 [kg/m2] and the annual production is 3 million tons. The use of geostatistical block kriging enabled to determine relative standard kriging errors as a measure of the accuracy of estimates of nodule resources. To minimize the risk of mining investment, it was assumed that the nodule resources estimation error in the case of calculation blocks corresponding to the areas of annual exploitation must not exceed 5%. The calculated estimation errors range from 10.6% to 26.6% (with a median equal to 13.1%) and are much higher than the assumed threshold value of 5%. The low accuracy of polymetallic nodule resources estimation is due to the small volume of samples collected by box corer, the large distance between sample collection points, and a relatively high regional (with a coefficient of variation close to 40%), and local variability in the abundance of nodules (discontinuous variation) as indicated by the nugget effect in the geostatistical semivariogram. Subsequent simulations have confirmed that achieving the assumed accuracy would require the collection of a large number of samples from the ocean floor, which is unrealistic given the huge labor intensity and high costs. The only rational way to achieve the assumed accuracy is to combine resource estimates based on box corer sampling method with an additional polymetallic nodule resources estimation based on bottom photographs, taken by the research ship or AUV (Autonomous Underwater Vehicle).
Publication Impact Profile
Publication details
References13
Chan-Young Park, Seung-Ho Park, Choon-Woo Kim, Jung-Keuk Kang, Ki-Hyune Kim, An Image Analysis Technique for Exploration of Manganese Nodules, Marine Georesources and Geotechnology, 17:4, 371-386, DOI: 10.1080/106411999273684, 1999.
Deutsch C.V., Journel A.G., GSLIB Geostatistical Software Library and Users Guide. Oxford University Press, 340 p., 1992.
Felix D., Some problems in making nodule abundance estimates from sea floor photographs, Marine Mining, 2(3), pp 293-302, 1980.
Isaaks, E.H., Srivastava, R.M., An Introduction to Applied Geostatistics, Oxford University Press, New York, 561 p., 1989.
Journel, A.G., Huijbregts, C.J., Mining Geostatistics. London Academic Press, 600 p., 1978.
Kotliński, R.A., Activities of the Interoceanmetal Joint Organization (IOM) in relation to deep seabed mineral resources development, Proc. Seabed: The New Frontier, ISA, Madrid, Spain, 29 p., 2010.
Mucha J., Wasilewska-Błaszczyk M., Estimating the resources of polymetallic nodules in the Pacific on the basis of their genetic characteristics and geostatistical methods (Clarion-Clipperton Zone, The Interoceanmetal area), Proc. of 18th International Multidisciplinary Scientific Geoconference SGEM2018, 2 July – 8 July 2018, Albena, Bulgaria, vol. 18, is. 1.3, Exploration and Mining, pp 407-414, 2018.
Mucha J., Wasilewska-Błaszczyk M., Kotliński R.A., Maciąg Ł., Variability and Accuracy of Polymetallic Nodules Abundance Estimations in the IOM Area – Statistical and Geostatistical Approach, Proc. of the Tenth ISOPE Ocean Mining and Gas Hydrates Symposium, ISOPE OMS, Szczecin, Poland, September 22-26 2013, International Society of Offshore and Polar Engineers, pp 27-31, 2013.
Okazaki M., Tsune A., Exploration of polymetallic nodule using AUV in the central equatorial pacific, Proc. of the ISOPE Ocean Mining Symposium, Szczecin, Poland, September 22-26, pp. 32-38, 2013.
Park S.H, Kim D.H., Kim C.W., Park C.Y., Kang J.K., Estimation of coverage and size distribution of manganese nodules based in image processing Techniques, Proc. of the Second Ocean Mining Symposium, Seoul, Korea, November 24-26, 1997, The International Society of Offshore and Polar Engineers ,40-44, 1997.
Sharma R., Khadge N.H., Sankar S. Jai, Assessing the distribution and abundance of seabed minerals from seafloor photography data in the Central Indian Ocean Basin, Int. J. Remote Sens., vol. 34, 1691-1706, 2013.
Schoening T., Kuhn T., Jones D.O.B., Simon-Lledo E., Nattkemper T.W., Fully automated image segmentation for benthic resource assessment of poly-metallic nodules, Methods in Oceanography, vol. 15-16, pp. 78-89, 2016.
Tsune A., Okazaki M., Some Consideration about Image Analysis of Seafloor Photographs for Better Estimation of Parameters of Polymetallic Nodule Distribution, Proc. of the Twenty-fourth International Ocean and Polar Engineers (ISOPE), Busan, Korea, June 15-20, pp. 72-77, 2014.
Citing literature
Number of times cited according to Crossref: 2
View or Download full articleAccess options
SWS access login
Login as SWS Scientific CommitteeLogin as SWS Scientific PartnerLogin as SWS AuthorAuthors and approved SWS contributors will read and export their own linked papers after identity matching by SWS profile, email and SGEM GlobalID.
For librarian assistance: [email protected]
Purchase Instant Access
- Article can be downloaded after successful payment.
- Article may be used according to SWS library access terms.
- Article cannot be redistributed.
