Determining uranium concentration in boreholes using wireline logging techniques: comparison of gamma logging with prompt fission neutron technology (PFN)

Penney, Richard K.; Ames, Caleb; Quinn, Dan; Ross, Angus Ian

doi:10.1179/1743275812y.0000000022

Cited by 9 publications

(8 citation statements)

References 4 publications

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“…Skidmore (2007) has reported that detection limit of their used PFN instruments were 0?025% U 3 O 8 and therefore they limited the application of the method to ore grade intersections. However, the 3rd generation of KND instruments developed in USSR and currently used in the post-Soviet republics, reportedly have detection limits in the range of 0?005-0?008% U 3 O 8 (Drobov, unpublished data) PFN instruments need to be calibrated against known standards including consideration of the moisture content and salinity of water (Penney et al, 2012). PFN quality control includes weekly calibration and reconciliation of PFN grades against XRF core assays.…”

Section: Prompt Fission Neutron (Pfn) Analysermentioning

confidence: 99%

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Resource estimation ofin situleach uranium projects

Abzalov

Drobov²,

Gorbatenko³

et al. 2014

Applied Earth Science

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Sandstone-type uranium deposits contain approximately 28% of the world uranium resources. Many of these deposits are located below the water table in weakly lithified or non-consolidated sands, and therefore they can be exploited using in situ leach (ISL) technology. Such technology is based on dissolving uranium minerals directly in their host rocks (in situ) by reactive solutions that are injected through drill holes and then pumping the dissolved solution to the surface through some discharge drill holes. Uranium grade is determined by down-hole geophysics, in particular the prompt fission neutrons, or PFN, technique, coupled with sampling and assaying of the drill core. The drill grid which is used in Kazakhstan for definition of ISL uranium resources are as follows: (i) Measured: average 506100 m (range from 25650 to 506100 m); (ii) Indicated: average 506200 m (range from 506100 to 506200 m); and (iii) Inferred: average 506400 m (range from 506400 to 1006800 m). Estimation and reporting of uranium resources for ISL projects differ from hard rock mining projects in the need for quantitative estimation of the geotechnical and hydrogeological parameters which are specific for ISL technologies. The main parameters which need to be considered are as follows: (i) grade and geometry of mineralisation are estimated with accuracy sufficient for supporting the remote mining; (ii) if grade is estimated using the gamma logging technique secular disequilibrium should be studied and reported; (iii) hydrogeological confinement of the mineralised horizon; (iv) permeability of the mineralised horizon; (v) composition of the host rocks, in particular the carbonate content, in order to estimate if uranium mineralisation is amenable to dissolution by acid or alkaline solutions; (vi) groundwater flow; (vii) aquifer salinity; and (viii) rate of the in-situ dissolution of the uranium minerals. Hydrogeological and geotechnical information is obtained by testing the drill core samples and in the field, using the pump tests and the down-hole piezometers. Modifying factors for conversion resources to reserves are verified and corrected using field leach tests of uranium. This test is a strict requirement for feasibility studies of the ISL uranium projects in Kazakhstan.

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Section: Prompt Fission Neutron (Pfn) Analysermentioning

confidence: 99%

“…A PFN is a geophysical technique which overcomes the gamma-ray technology gap for disequilibrium (Penney et al, 2012). The PFN method uses a pulsed neutron source for emitting high energy neutrons to the rocks and it records the ratio of generated epithermal neutrons to thermal neutrons.…”

Section: Prompt Fission Neutron (Pfn) Analysermentioning

confidence: 99%

Resource estimation ofin situleach uranium projects

Abzalov

Drobov²,

Gorbatenko³

et al. 2014

Applied Earth Science

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“…This is conditioned by the high cost of core drilling. The lack of reliable information on the lithological structure of the productive horizon section during well construction, which is conditioned by the lack of a sufficient amount of core material, can be compensated for by conducting a complex of geophysical well logging (Geologic Information System, GIS) [8].…”

Section: Introductionmentioning

confidence: 99%

Application of radio-wave geointoscopy method to study the nature of spreading the solutions in the process of uranium underground leaching

Tsoy¹,

Myrzakhmetov²,

Yazikov³

et al. 2021

Min. miner. depos.

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Purpose. Assessment of the effectiveness of using the method of radio-wave geointoscopy of the inter-well space for three-dimensional mapping of the zone of the leaching solution actual propagation in the process of uranium mining by the method of underground leaching. Methods. Experimental-industrial studies of the leaching process are conducted at technological block 68 of the Semizbay deposit (Kazakhstan). In experimental studies, special equipment is used for conducting radio-wave geointoscopy. Inter-well measurements are performed using the RVGI-06 equipment. The observations are conducted in a fan pattern within the filter section. The step between adjacent points along the wellbore is 1 m. At different stages of mining the technological block, maps of geoelectric resistivity have been compiled, with the help of which a comparative analysis is performed. Findings. A tendency to an increase in the area of acidic solutions propagation over time has been revealed by comparing the fragments of RVGI geoelectric map at different stages of mining the block. The influence of a heterogeneous geological structure on the uniformity of the leaching solutions propagation has been proved. It has been determined that the resolving power of the radio-wave geointoscopy method is sufficient to detect changes in geoelectric conditions at small monitoring cycles in time. The spatial-temporal change in the front of the leaching solutions propagation makes it possible to determine the prevailing directions of solutions propagation and to assess the filtration characteristics of rocks. Originality. The patterns have been determined of the leaching solutions propagation over time from the beginning of block acidification to active leaching. The first attempts have been made to use the geophysical well logging method in the practice of uranium mining by In-Situ Leaching (ISL) method. Practical implications. Monitoring studies by radio-wave geointoscopy method at the stage of passive acidification can be re-commended for further experimental and scientific testing at technological blocks of the Semizbay deposit for a quantitative assessment of the filtration characteristics of rocks and the dynamics of the acidification process development, as well as for the development of well-grounded recommendations on the optimal scheme for mining the blocks in specific geotechnical conditions.

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“…The tra di tional bore hole logging tech nique of ex plor ing ura nium de pos its and quan ti fy ing the grade of the ura nium, by spec tral g ray (SGR) log ging mainly, is used to mea sure the spectrum of g rays emit ted via nat u ral ra dio ac tiv ity of uranium ( 238 U and 235 U), tho rium ( 232 Th and 230 Th), and po tas sium ( 40 K) in the bore hole for ma tion. These radio ac tive iso topes emit g rays with char ac ter is tic energy level and can be used to quan tify the grade of uranium in the de posit [1].…”

Section: Introductionmentioning

confidence: 99%

A union neutron-gamma logging method for determination of uranium-radium disequilibrium coefficient

et al. 2020

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Owing to the influence of continuous running of ground water, the uranium atoms can be separated physically from their daughters for the reason of different solubilities and the uranium deposit often shows the disequilibrium feature between uranium and its daughter products (radium principally). It is important, when spectral gamma ray logging, to quantify the uranium content which can cause inaccuracy of the result. This paper, based on spectral ? ray logging method, proposes a neutron-gamma logging method to determine the coefficient of uranium-radium disequilibrium. In this method, characteristic peak count rate of uranium is taken from prompt fission neutron logging, whereas characteristic peak count rate of radium, thorium and potassium are taken from spectral gamma ray logging. Based on this method, the union logging tool including epithermal neutron, thermal neutron, and gamma detector along with D-T generator, have been developed. The experimental results, in standard model wells, show that this method is in good agreement within 7% in core assay results. It shows that the union neutron-? logging method can be used for field uranium logging jobs.

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Determining uranium concentration in boreholes using wireline logging techniques: comparison of gamma logging with prompt fission neutron technology (PFN)

Cited by 9 publications

References 4 publications

Resource estimation ofin situleach uranium projects

Resource estimation ofin situleach uranium projects

Application of radio-wave geointoscopy method to study the nature of spreading the solutions in the process of uranium underground leaching

A union neutron-gamma logging method for determination of uranium-radium disequilibrium coefficient

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