RU2554657C1 - Method of detecting rubin-containing calciphyres - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method of detecting rubin-containing calciphyres includes selection of calcite monofractions from alternating zones of calciphyres followed by determining the presence of ruby mineralisation. In selected samples of calcite the luminescence is excitated in the optical wavelength range, and the areas are determined with the presence of ruby mineralisation on a sharp drop in the intensity of radiation in the wavelength range of 600-640 nm.

EFFECT: cost reduction, increased rapidity and reliability of the preliminary assessment of ruby mineralisation.

5 dwg

Description

The invention relates to the field of geology, development and use of mineral deposits and can be used at various stages of prospecting and exploration to identify ruby mineralization. Ruby is a precious variety of the corundum mineral (noble corundum). Deposits of noble corundum are very rare. The most important root sources of noble corundum are calciphyres containing ruby mineralization. Ruby and the minerals associated with it are characterized by low-power zones of mineralization development, within which they form rare disseminated impregnation and separate nests. This form of localization of ruby makes it difficult to find. In this regard, it becomes relevant to develop new search and evaluation methods based on the study of the properties of rock-forming minerals associated with ruby. The rock-forming mineral in calciphyres accompanying ruby is calcite. A known method for diagnosing ruby-containing calcifiers using X-ray diffraction analysis is that radiographs are taken for the samples of rock-forming mineral calcite to be examined, after decoding of which, using the diagnostic tables, it is determined whether there is ruby in this sample (Mikheev V.I. ., State Scientific and Technical Publishing House of Literature on Geology and Mineral Resources Protection - 1957 - S. 375-376). The disadvantage of this method is the fact that this method can determine ruby only if its content in the sample is at least one percent. There is also a known method for diagnosing ruby using luminescent analysis, when the presence of ruby in a test sample of a rock-forming mineral is judged by the appearance of intense narrow emission bands of Cr ³⁺ in the spectral range of 690-700 nm under the influence of an x-ray or optical excitation source. The fact is that Cr ³⁺ ions, replacing Al ³⁺ ions in the structure, are luminescence centers in corundum (ruby). The disadvantage of this method is the fact that ruby forms a rare disseminated impregnation among the host rocks. With this form of localization, a rare sample of the enclosing rocks may contain interspersed ruby even within the deposit or manifestation of ruby. The mineralogical method for detecting ruby is also known, which consists in the fact that visually or using a microscope, the minerals associated with ruby are determined - indicators of possible mineralization (fuchsite, chrome diopside, chromtremolite), and by their presence they conclude that there is ruby mineralization (Rossovsky L.N. , Konovalenko S.I., Ananiev S.A. Conditions for the formation of ruby in marbles // Geology of ore deposits. 1982. No. 2. P. 57-66). The disadvantage of this method is the fact that ruby and the minerals associated with it (fuchsite, chrome diopside, chromtremolite) form a rare disseminated impregnation in low-power zones of mineralization development and can be skipped even with a detailed study of enclosing calciphyres and marbles. The mineralogical and geochemical method for detecting ruby mineralization is also known, which consists in taking calcite samples, examining their chemical composition for detecting trace elements of Mg, Mn, Fe and identifying areas with ruby mineralization by changing their concentration in calcites. The authors of the known method experimentally found that ruby-containing interlayers are characterized by minimum concentrations of all the main impurity elements (Mg, Mn, Fe) in rock-forming calcite (Konovalenko S.I., Bazhenov V.A., Novgorodtseva T. Yu. Using calcitometry methods for the search for metamorphogenic deposits of ruby / Methodological foundations of the search and exploration of non-metallic mineral resources: Interuniversity collection of scientific papers. Geology, the search and exploration of non-metallic mineral resources. / Leningrad Mining Institute, L. 1988 - pp. 66-71 - prototype). Currently, the concentration of impurity elements, i.e. the chemical composition of the rock is determined using laborious and expensive methods: X-ray fluorescence analysis - X-ray diffraction (the method is based on the dependence of the intensity of the secondary characteristic radiation on the wavelength), mass spectrometry with inductively coupled plasma - ISP-MS (this method is based on inductively coupled plasma as a source of ions and a mass spectrometer for their separation and detection) or using quantitative spectral analysis. As a result, the disadvantage of this method is the complex preliminary preparation, a large investment of time, a large amount of the studied material and means for performing chemical analysis.

The objective of the present invention is to develop an express method for the detection of ruby-containing calcifiers in order to reduce cost, increase expressivity and reliability of a preliminary assessment of ruby mineralization.

The problem is solved in that, according to the prototype, monofraction of calcite is carried out from various alternating sections of calciphers, but unlike the prototype, the presence of ruby mineralization is determined by a sharp decrease in the radiation intensity in the luminescence spectra of impurity ions Mn ²⁺ in the spectral wavelength range of 600-640 nm in samples of calcite.

The choice of the spectral range of 600-640 nm is due to the fact that it is in this wavelength range that Mn ^{2+ ions are} emitted, replacing calcium in the structure of calcite (Tarashchan A.N. Luminescence of minerals. - Kiev: Nukova Dumka, 1978. - 298 p. ) The authors of the present invention experimentally established the pattern that calcite samples taken in areas with ruby mineralization have a Mn ²⁺ emission band in the luminescence spectra in the spectral range 600-640 nm, which is an order of magnitude weaker than that in calcites taken outside the ruby mineralization (Fig. 1). Figure 1 shows the luminescence spectra of calcite obtained by x-ray excitation (X-ray luminescence spectra). It can be seen from Fig. 1 that the intensity of X-ray luminescence (RL) of calcite taken from a zone with ruby mineralization is an order of magnitude weaker than the intensity of X-ray luminescence of calcite taken from a zone without ruby mineralization. This fact can be associated both with a decrease in the concentration of Mn ²⁺ impurity in areas with ruby mineralization, and with a change in the acidity-alkalinity of the mineralization medium directly in these zones. It is known that the entry of Mn ²⁺ into the Ca ²⁺ site ^is hindered by an increase in the alkalinity of the mineral formation medium (Korzhinsky, D. S. Acid-base interaction in mineral-forming systems: Selected Works / M .: Nauka, 1994. - 223 p.), Which is reflected in the X-ray luminescence spectrum of calcite, which consists in the fact that there is a noticeable decrease in the radiation intensity of impurity ions Mn ²⁺ .

 Examples of carrying out the invention

The studies were carried out on calcite samples from deposits of noble corundum in the Southwestern Pamirs, Burma and the Ormizan deposit (Tien Shan folded region), Calcite was selected for luminescence analysis according to alternating zones within the zonal areas with the expected ruby mineralization and beyond. The URS-55 apparatus and the BSV-2 x-ray tube were used as a source of luminescence excitation. The X-ray luminescence spectra obtained with this excitation were recorded using an MDR-12 monochromator. The radiation intensity is given in arbitrary units. Moreover, 1 conventional unit in this case is approximately equal to 10 ^-3 nits.

Example 1

A sample of calcite (10 mg) was taken from a calciphyre site with visible ruby mineralization in the Southwestern Pamirs (sample 1) and another calcite sample (10 mg) - sample 2 - outside the area with ruby mineralization. For both samples, X-ray luminescence spectra were obtained in the spectral wavelength range of 550-700 nm. According to the intense radiation of sample 2 in the spectral range 600-640 nm (up to 150 conventional units), this area where sample 2 was taken is classified as barren, i.e. not bearing ruby mineralization. According to the weak radiation of sample 1 in the spectral range of 600-640 nm (up to 15 conventional units), which is an order of magnitude weaker than the radiation of sample 2, this section was assigned to the zone with ruby mineralization (Fig. 1). The reliability of this determination was confirmed by a direct finding of the ruby mineral within the area where sample 1 was taken. In addition, the reliability of this determination was confirmed by the mineralogical and geochemical method of detecting ruby mineralization (Konovalenko S.I., Bazhenov V.A., Novgorodtseva T. Yu. The use of methods of calcitometry in the search for metamorphogenic ruby deposits / Methodological foundations of the search and exploration of nonmetallic minerals: Interuniversity collection of scientific papers. Geology, searches and dka non-metallic minerals. / Leningrad Mining Institute, L., 1988. - S. 66-71). We studied the chemical composition of samples 1 and 2 in order to detect microimpurities of Mg, Mn, and Fe, according to the change in the concentration of which in areas of calcite previously identified areas with ruby mineralization. The low contents of Mg (0.12%), Mn (0.003%) in sample 1 confirmed that this sample belongs to the zone of ruby mineralization. The increased contents of Mg (6.8%), Mn (0.018%) in sample 2 confirmed that this sample belongs to the barren zone, i.e. to the zone without the manifestation of ruby mineralization. The content of impurity elements was determined by quantitative spectral analysis in the research laboratory of the geological and geographical faculty of TSU (analyst Tsymbalova EM).

Example 2

We prepared two samples of calcite (P-3 and P-4) from zones with possible mineralization (South-Western Pamir). X-ray luminescence spectra were obtained on the prepared samples. According to a very weak calcite radiation in the spectral range 600-640 nm (up to 23 arb), comparable with the low-intensity radiation of sample 1 from Example 1, this area, where samples P-3 and P-4 were taken, was attributed to the ruby mineralization (Fig. 2). The reliability of this selection was confirmed by analytical data similar to example 1. Low Mg (0.12-0.13%), Mn (0.003%) in P-3 and P-4 calcite samples confirmed that these samples belong to areas of ruby mineralization .

Example 3

We prepared three samples of calcite (10 mg each) from the medium-grained, sugar-like grayish-white calciphyre with graphite mineralization (Ormizan deposit) - samples Or-5, Or-6, Or-7. X-ray luminescence spectra were obtained on the prepared samples. By very weak calcite radiation in the spectral range of 600-640 nm (from 8 to 11 conventional units) in all three samples, which in terms of radiation intensity is comparable to low-intensity radiation of samples 1, P-2, P-3 and more than an order of magnitude inferior to samples 2 (Example 1), Or-8 and Or-9 (Example 4), this zone, where the samples Or-5, Or-6, Or-7 were taken, is assigned to the zone bearing ruby mineralization (Fig. 3 ) The reliability of this definition is confirmed by the data of luminescent analysis. From Fig. 3 it follows that in the spectrum of one of the samples (Or-5 sample), Cr ³⁺ radiation was recorded in the range of 690-700 nm, which indicates the presence of ruby in the Or-5 sample in the form of an impurity.

Example 4

We prepared two samples of calcite (10 mg each) taken from a grayish-cream calciphyre zone with a fine-grained structure (Ormizan deposit) —Or-8 sample and Or-9 sample. For both samples, X-ray luminescence spectra were obtained in the spectral wavelength range of 550-700 nm. According to the very intense calcite radiation in the spectral range 600-640 nm (200-270 conventional units), comparable with the luminescence of sample 2 (Example 1), this zone, where the samples were taken, Or-8 and Or-9, is assigned to barren, those. not bearing ruby mineralization (Fig. 4). The reliability of this definition is confirmed by the data of mineralogical and geochemical studies described in Example 1. Elevated contents of Mg (6-11%), Fe (0.3-0.7%), Mn (0.018%) in samples Or-8 and Or- 9 confirmed that this sample belongs to the barren zone, i.e. to the zone without the manifestation of ruby mineralization.

Example 5

A sample of calcite B-1 (10 mg) was prepared from the calciphyre zone with the estimated ruby mineralization (Burma). An X-ray luminescence spectrum in the optical wavelength range was obtained for the prepared sample. By very weak calcite radiation in the spectral range 600-640 nm, which is comparable in radiation intensity with low-intensity radiation of samples 1, P-2, P-3, Or-5, Or-6, Or-7 and is more than an order of magnitude inferior to samples 2 (Example 1), Or-8 and Or-9 (Example 4), this zone where the B-1 sample was taken is assigned to the zone bearing ruby mineralization (Fig. 5). The reliability of this definition is confirmed by the mineralogical method, i.e. a direct find of the ruby mineral within the area where sample B-1 was taken.

Thus, the proposed method allows you to quickly and reliably on a small amount of the investigated material to identify areas with ruby mineralization.

Claims (1)

 A method for detecting ruby-containing calcifiers, including sampling monofractions of calcite from alternating zones of calcifiers with subsequent determination of the presence of ruby mineralization, characterized in that in the selected calcite samples, luminescence is excited in the optical wavelength range and zones with the presence of ruby mineralization are determined by a sharp drop in radiation intensity in the range of radiation intensities in the range waves of 600-640 nm.

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