INNOVATORS OF ZINC -SMALL CHANGES USUALLY ADD UP TO HUGE RESULTS...

Reducing Breakdowns by In-house designing of Loader bucket…
Komatsu Loader WA900 having 13 cubic meter bucket capacity, is one of the largest Loaders used in Mining Industry. At Rampura Agucha Open Cast Mine, this Loader is used at primary crusher pad for ore feeding.  But RA-OC team has been a facing a major challenge in the Loader, its tooth points would often wear off from the mounting pin and fall into crusher resulting in crusher breakdown. Also, the life of tooth point was very short.
To reduce the crusher breakdown and to increase the life of tooth point of the bucket, Heavy Earth Moving Machine (HEMM) team consisting Mr. Krishankant Tripathi (Executive- HEMM), Mr. Sachin Kumar (Engineer- Mining Machinery) and Mr. Arjun Kumar (HOD-HEMM) took the challenge to change the design of the Loader bucket. After studying the technicalities involved, the complete bucket front lip was re-designed by the team indigenously and manufactured through local agency. Tooth Point of different design was also fitted in the bucket.
The results were remarkable. Since then, there is not a single case of premature wearing of tooth point in the new design of bucket. The life of new tooth point is twice the original. The cost of ground engaging tools for the equipment went down from Rs. 1538/ hour in FY 2015-16 to only Rs. 415/ hour in FY 2016-17 which gave a direct saving of Rs. 36 lakh y-o-y and, eliminated indirect losses due to breakdown of the equipment and crusher. 

INNOVATORS OF ZINC - WHAT GETS MEASURED; GETS MANAGED…

Induced Fan Duct is a critical equipment of Boiler in Captive Power Plant (CPP) and its malfunction would lead to breakdown of boiler. CPP at Chanderiya has been facing a major challenge of erosion of duct parts of Induced Draft Fan, leading to higher power consumption, thereby, increasing COP.
To eliminate the erosion, Captive Power Plant team comprising Mr. Mahender Singh Rathore (Manager -  Engineer and Planning), Mr. Seela Satyanarayana (Associate Manager - Electrical), Mr. Mohd. Parvez (Associate Manager - Power), Mr. Chandi Das (Associate Manager - Electrical) and Mr. Binu Raphael (AGM - Asset Optimisation) conducted a detailed “Computational Fluid Dynamics” analysis by taking measurement of pressure drop across the duct. Huge pressure drop across the duct was found to be the main reason of erosion during the analysis. Team then rectified the flow path of induced air by modifying the design of the duct.
Team efforts paid result. After design modification, the erosion of duct got reduced and power saving of around 100KW/Unit was achieved leading to cost saving of Rs.
30 lakhs per annum. This has been horizontally implemented across all units of HZL.

INNOVATORS OF ZINC - WHEN INDUSTRY ACKNOWLEDGED HINDUSTAN ZINC’S EXCELLENCE AND LEADERSHIP IN MINING INDUSTRY

It is said.. “If you thrive for Excellence … You Get It..”

Mr. Ashutosh Pathak, Geologist - Mochia Mines at Zawar, and the geologist team went for a training programme on "Mineral deposit evaluation: Resource estimation, classification and reporting" held at Hyderabad from 17th to 20th  April'17. The training also saw participation from organizations like Tata Steel, NMDC, GSI, MECL, IMFA, etc. to name a few.

To understand the level of technology the mining companies are using, the faculty raised many questions. These pertained to software used in mining industry and exploration equipments.  Mr. Ashutosh Pathak has informed that Hindustan Zinc was the clear leader in all the present gallery of industries as Hindustan Zinc was the only company to have:

1. Mineral reporting as per CRIRSCO guidelines and we use JORC code, which is rare in the industry.

2. Use of advanced geological software like Data-mine and leap-frog for geological modelling as Hindustan Zinc is the first company in the country to introduce leapfrog.

3. Using high drilling capacity rig known as MCR first time in India for underground exploration drilling.

4. Using Geo stat tool very effectively for mineral estimation at every mine location of Hindustan Zinc.

5. Using best EDA techniques to ensure the reliability and accountability of database to create final reserve and resource estimates.

6. For R&R reporting a code being generated in India.

Other team members included – Mr. Vivek Tyagi (AM Geology – Kayad), Mr. Pankaj Choudhary (AM – Geology –SK Mine), Mr. Anand Pandey (Geologist – CRDL) and Mr. Biswajit Basak (Geologist – Zawar).

INNOVATORS OF ZINC - AUTOMATION IN REACTORS ELIMINATED RISK AND ELIMINATED MAN-MACHINE INTERACTION

Residual Treatment Plant (RTP) is a part of Leaching and Purification area in smelters. It is also called Jarosite Precipitation (JP) area.

There are total of 5 Reactors having a capacity of 300 cubic meters each at Zinc Smelter Debari. These reactors are equipped with agitators and steam coil for heating process solution to 100 degree centigrade.

The challenge was that if the agitator of any reactor fails, the steam would continue to flow through control valve to the reactor. As there would be no mixing of solution due to failure of agitator, solution near steam coils would heat rapidly and could lead to explosion of the reactor. The control valve would only be closed manually and that involved great amount of risk as well as process inefficiency.

A team consisting Mr. Vijay Kumar Rana (AM - Process), Mr. Sanjay Kumar (AM - Instrumentation), Mr. Debasis Sahoo (Engineer - Process) and Mr. Sandip Kanani (AM - Mechanical) felt the need for a change in this whole process and automation with steam auto valve cut-off seemed to be the solution.

Once this modification was done, it is ensured that if agitator of any reactor trips, the amperage of the reactor will drop down to no load level and the valve will close automatically preventing the steam entrance into the reactor.

This automation resulted in elimination of major hazard and also eliminated man machine interaction in reactors. It also resulted in power saving and increasing productivity.

INNOVATORS OF ZINC - PRODUCING 200M3 WATER PER DAY FROM UNUSED STEAM…

Hydro-I plant at Chanderiya Smelting Complex, commissioned in 2005 generated about 43-45 tonnes of steam from Waste Heat Recovery Boiler which is used to generate power in condensate type turbine of 9.40 MW. During this process, about 25 tonnes of steam gets condensed and remaining 20 tonnes is used for leaching process. Since leaching LP steam requirement is about 35 tonnes, the remaining 15 tonnes steam needs to be taken from CPP.
To reduce the cost of steam from CPP, in 2012 condensate type turbine was replaced by 4.3 MW back pressure type turbines. Due to this, the excess steam of 6-8 tonnes/hr started venting off through final vent. This contributed to water loss of about 150 m3/day.
A team comprising Mr. Deepak Jain - AM, O&M, Mr. Kailash Chandra Choubisa - AM, E&I, Mr. Sunil Dutta - Executive, O&M, Mr. P.C. Kumawat - AM, O&M, Mr. Bhagwan Lal Dhakar - Executive, O&M of Unit-II under guidance of Mr Rajesh Luhadia - Unit Head, Unit-2  brain-stormed for utilization of this vent steam as part of water conservation project.
The team came up with an innovative idea to utilize the available spent heat exchanger to arrest the unutilized 6-8 tonnes of vent steam.
A condensing system was connected before the final vent to convert the excess steam into condensate water and recycled the same into the boiler circuit. Due to additional in-built capacity of condensing system, vent steam of Hydro-2 Roaster could also be condensed with the same system. This lead to water recovery of more than 200m3/day against target of 130m3/day from unused steam.

INNOVATORS OF ZINC - RECOVERY OF ZINC FROM SLAG IN LEAD AUSMELT PLANT BY OPTIMIZING IRON AND SILICA RATIO IN CONCENTRATE

The Ausmelt furnace at Chanderiya produces Lead bullion using Lead concentrate and is designed to handle 3.9% Zinc and 5% Graphitic Carbon. Higher Zinc in this concentrate results in higher Zinc percentage in slag and higher Graphitic Carbon results in poor separation of slag from Lead bullion. It also lowers the life of the lance.

Since September 2016, Ausmelt plant was getting Lead concentrate with 6-9% of Zinc and 5-16% of Graphitic Carbon which was more than the optimal percentage of Zinc and Graphitic Carbon.

A team led by Mr. Pranabesh Roy - SBU Head and comprising Mr. T.V.S.S. Nagaraju - AM, Process, Mr. Vinay Kanthalia - AM, Process, Mr. Shyam Goswami  - Jr. Executive, Process, Mr. Vivek Menaria - Jr. Executive - Process, Mr. Sandeep Paliwal - AM, Mechanical and Mr. Anil Inani - AM, Instrumentation as team members took the task to overcome this challenge.

It was studied and observed that when the ratio between Iron to Silica (Fe/SiO2) is more than 0.9 and Zinc is above 20-22% it results in formation of severe build-up inside the furnace. Also, to control bath temperature due to high Graphitic Carbon, Ausmelt furnace needs at least 25-30 MT/day of extra secondary material. The only in-house secondary material available was ISF dross which contains 25-30% Zinc and 55-60% Lead.

The team studied the effect of Zinc and other impurities like Iron & Silica in slag. To maintain the ration of Iron to Silica (Fe/SiO2) below 0.9, Silica was added as flux which brought down the ratio to 0.6 to 0.7 and thus was able to handle 32-35% Zinc in slag.

The team was successful to use high Zinc and Graphitic Carbon concentrate and was able to consume 800-1000 MT per month of ISF dross inventory which otherwise was increasing every month. Optimization of this slag chemistry also helped to get highest lance life ever (6 batches per lance) for the month of December 2016 with record of 16 batches for a single lance. This increased the average life of lance by 3 times.

INNOVATORS OF ZINC - DISCOVERING CWM-SERIES OF LENS WITH HIGH METAL CONTENT AT ZAWAR…

Zawar Mines, one of the oldest mines, is all set for expansion and has planned to increase its production capacity in upcoming years. The goal is to produce 4 million tonnes of ore from all the four underground mines in Zawar.
 Mochia, the oldest mine of Hindustan Zinc has planned to contribute 1.2 million tonnes in terms of ore production. To reduce the pressure of production, it was necessary for the mining team to keep two or three stopes ready all the time. For this, the team required sufficient Reserves and Resources to meet the planned production targets.
 At West Mochia section, there exist a series of lenses called CWM-Series of lenses. These lenses possess significant potential but were completely untouched in terms of production. The intersections of these lenses were at greater distance from surface but remained unexplored from underground at shallow depths.
 Mochia Geology Team comprising Mr. Ashutosh Pathak (In-charge, Geology Department-Mochia),  Mr. Santosh Kumar Guin (Geologist), Mr. Prashant Biswas (Geologist) and Mr. Sayandeep Chakraborty (Geologist) decided to utilise this unexplored resource below the earth at shallow depth from surface and identified this area for exploratory drilling. The team drilled around 2800 metres of these lenses and added about 9 lakh tonnes of R&R with 5% Total Metal Content in just a year which is sufficient to cater to the needs of Zawar during development stages.
The team has planned further drilling and production from this area in the upcoming times which will divide the pressure of production from other stopes and help in meeting the goal of 4 million tonnes.

INNOVATORS OF ZINC - INDIGENOUS DEVELOPMENT OF MOTORS SAVES RS. 40 LAKHS AT ZAWAR…

Indigenous development of motors saves Rs. 40 lakhs at Zawar…

Indigenous efforts of Hindustan Zinc have always proved and contributed towards reduction of costs and increase in volumes. One such effort saved Rs. 40 lakhs by indigenously developing OEM motors that were initially being imported. This is a case study of a team at Zawar Mines that brought down cost drastically by finding alternatives through in house research process.

The LOCO system in Zawar was very old and was leading to failure and subsequent breakdowns.  This was becoming the reason for substantial mine production loss. Thus, it was felt to replace the existing motors with a new set of motors.
Since the new set of OEM motors were costing around Rs. 24 lakhs it was felt to look for other possible opportunities to meet the requirements. A team led by Mr. Jorawar Singh (Commercial Head) and Mr. Tamil Selvan (AGM - Electrical) along with Ms. Apoorva Vyas (AM - Commercial) as its member started looking for opportunities and decided to opt for indigenously developed vendors in India by providing them with necessary technical details.
The efforts paid results. The team was successful in developing and procuring the same motor in India without the help of OEM and at a much reduced cost of just Rs. 4 Lakhs per motor.
Two motors were initially procured and installed in LOCO system and since the last 10 months the LOCO machines have been running smoothly and have also led to a saving of Rs. 40 lakhs.