Mineralogical Study of Zard Koh and Kulli Koh Iron Ore Deposits of Pakistan

Zard Koh and Kulli Koh are two recently discovered iron ore deposits, existing in the Chagai district, Balochistan, Pakistan. PSM (Pakistan Steel Mill Limited) is interested to utilize these ore deposits at priority. Purpose of the present study was to assess the mineralogy of the Zard Koh and Kulli Koh iron ore deposits, as it plays a vital role in the selection of an appropriate processing method. The mineralogical study of ore deposits was carried out by XRD (X-Ray Diffraction), XRF (X-Ray Fluorescence), SEM (Scanning Electron Microscope) attached with EDS (Energy Dispersive Spectroscope) and SM (Stereomicroscope) techniques. Results indicated that the Zard Koh ore is mainly composed of 60.15% maghemite, 23.57% pyrite, 4.07% chlorite, 10.30% grossular and 1.65% admontite minerals. The chemical analysis revealed that Zard Koh iron ore contains an average of 54.27% Fe, 12.73% S, 8.70% Si, 3.07% Al, 4.07% Ca, and 2.16% Mg. Similarly, the mineralogical study of the Kulli Koh iron ore indicated that, ore is containing 51.16% hematite, 29.24% quartz, 8.89% dravite, and 8.76% kaolinite minerals. Elemental analysis of different samples indicated that Kulli Koh iron ore contains an average composition of 40.23% Fe, 20.67% Si, 3.44% Ca, 3.81% Al and 3.25% Mg. Mineralogical study of the Zard Koh and Kulli Koh iron ore deposits suggested that these ore deposits can be beneficiated costeffectively by using magnetic separation techniques.

Geologically, the Dalbandin iron deposits are associated with sanjrani volcanic [1]. PSM is interested to utilize these national assets for the production of iron and steel at priority. However, these iron ores in their raw state cannot be used directly into the ore smelter, and require a satisfactory concentration technique for their up gradation. In this regards, beneficiation study of Zard Koh and Kulli Koh iron ores was carried out in the Department of Metallurgy & Materials Engineering, Mehran University of Engineering & Technology, Jamshoro, Pakistan. The mineralogical investigation has been made in the initial phase of the study in order to envisage the beneficiation technique. Therefore, the purpose of this paper is to present the mineralogy of the Zard Koh and Kulli Koh iron ore deposits evaluated while course of the beneficiation study.
Many researchers used various analytical techniques for the mineralogical study of natural iron ore body [2][3][4][5][6][7][8]. Mineralogical characterization of the Dilband iron ore deposits of Pakistan was carried out by XRD, EDS attached with EDS, XRF and SM techniques [2]. Mineralogical constituents of a low grade Indian iron ore were studied through XRD and SEM analysis [3]. XRF and EDS techniques were used for the elemental chemistry of ore samples, XRD for crystallography, and SEM and SM techniques were used for surface morphology of the samples [4][5][6].Using these techniques, mineralogy of Zard Koh and Kulli Koh iron ore deposits of Pakistan was successfully determined. It is worth mentioning here that, the mineralogical investigations of the Zard Koh and Kulli Koh ore deposits have not been reported as per the knowledge of the authors.

MATERIALS AND METHOD
The Zard Koh and Kulli Koh iron ore samples of different locations were received from PSM, Karachi. As received samples were in the form of lumps ranging in size from 7-10 cm. They were crushed and ground into different size fractions and then stored in air tight plastic bags. For the mineralogical study, different samples of each iron ore were analyzed under petrological, mineralogical and elemental analysis techniques. JEOL JSM-6380L SEM and Lieca SM were used for analysis of petrographic features, Bruker D-8 XRD was used for mineralogical study, and EDS attached with SEM and XRF spectrometer were used for elemental analysis. The operating parameters of the equipment used are reported elsewhere [9].

Mineralogy of Zard Koh Iron Ore
The XRD spectrums of the representative samples of Zard Koh iron oreare shown in Fig. 1 By using the XRF results as shown in Table 2, the SQ (Semi-Quantitative) analysis of these minerals was determined from each sample. The distribution of minerals in each sample is given in It can be seen from the SEM and EDS analysis given in Furthermore, it is widely acknowledged from the literature [4], that in SEM images the appearance of maghemite mineral is almost similar to that of pyrite. The elemental chemistry of the ore samples, given in

. SEM AND XRD ANALYSIS OF MAGHEMITE AND PYRITE RICH GRAINS
The SQ (Semi-Quantitative) analysis of each sample of the Kulli Koh iron ore is given in  Fig. 6(a-c), indicates that mostly the grains of four different appearances viz. black (sometimes with shining appearance), colorless, gray, and reddish particles are present in Kulli Koh ore. By using the optical properties of the minerals, the black particles with shining appearance were recognized as hematite, colorless grains as quartz, reddish as dravite and gray as kaolinite minerals respectively. During SM analysis, it was noted that the hematite grains showed different appearances. In few samples the hematite rich grains reflected the light with brilliant luster and appeared as shining grains (Fig. 6(b)), whereas in some cases its appearance was black (Fig. 6(a and c) (iii) Keeping in view the mineralogy of the ores and magnetic property of the valuable and gangue part, it is envisaged that magnetic separation for both minerals would be suitable technique to upgrade these ores.
(iv) The micaceous nature of hematite in the Kulli Koh ore deposits suggest that density separation technique would not produce good results.