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Mineral chemistry of biotite, chlorite and epidote associated with the granitoid ore body of the Malanjkhand coppermolybdenum deposit have been studied to constrain temperature, oxidation and sulfidation states as well as fugacity ratios of HF, HCl and H 2 O of the hydrothermal mineralizing fluid. Calculated mineralizing temperatures from biotite, chlorite and epidote are mutually consistent and agree well with earlier estimates derived from fluid inclusion studies. Major element chemistry of biotite indicates low oxidation state (FMQ-NNO) and re-equilibrated nature (~300°C). However, exchange of Cl-F-OH between biotite and the fluid continued to lower temperatures. Subtle differences between the Malanjkhand deposit and known porphyry copper deposits have been evidenced by the fugacity ratios of halogens and water. Chlorite registers equilibrium with fluid down to 200°C and, together with biotite composition, indicates that copper was transported as chloride complex in the fluid. Sulfide deposition occurred during a prompt rise in fugacity of H 2 S at 300°C, possibly resulting from a coupled oxidation of Fe 2+ and reduction of SO 4 2-. Interaction of ore fluid with epidote in the wall-rock favored the deposition of chalcopyrite, enhanced the Ca 2+ activity in the fluid and inhibited a fall in pH and a subsequent acid alteration of K-feldspar in the wall-rock. These physicochemical characteristics of the mineralized fluid suggest that the Malanjkhand deposit represents an ancient granitoid-associated geothermal system rather than a classic porphyry copper ore deposit.

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The manual decortication process of charoli seeds by beating the dried seeds on the ground with a hand hammer or stone and, by domestic grinder is a laborious, inefficient, time‐consuming as well as uneconomical process. Therefore, an attempt has been taken toward the automation of the charoli decortication process. The decorticator performance was evaluated at three levels of disc speeds, disc clearances, and different moisture levels of charoli seed viz. 197, 246, and 286 rpm; 6, 7, and 8 mm; and 7.83, 8.57; and 9.04% wb, respectively. The selected input parameters were optimized by using the response surface methodology (RSM). The optimum value of disc speed, disc clearance, and seed moisture content was found to be 197 rpm, 7 mm, and 9.04% (wb), respectively. The corresponding response values in terms of decorticating efficiency, whole kernel, and broken kernel percentage at optimum conditions were recorded as 92.5, 21.6, and 3%, respectively. Novelty impact statement The decorticating capacity of the developed decorticator was found to be 70 kg per hour which was higher than the existing decorticator. Since the developed machine was automatically operated and each unit operation was sequentially and continuously carried out with no manual intervention, the ideal time in each decortication step was absent and subsequently, higher capacity was achieved. The efficiency of the decorticator was found to be 92.5%. The higher capacity and kernel recovery with no human drudgery and lower cost of decortication imply the significance of the development of the machine.

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