Process

Minimise Fines, Maximise Coal Recovery

Published

8 years ago

January 31, 2017

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In coal mining, generation of fine (powder) material is an important factor to assess the quantum of useful material component. Optimising the fines content of run-of-mine coal offers numerous savings and benefits.

Most coal mines measure the particle size distribution (PSD) of their plant feed to obtain information about the suitability of the feed for their process, especially regarding the fines content. But few mines know where these fines come from exactly, and few still actually measure the fines content at the face to compare it to the plant feed data and to optimise the processes in between ‘ although optimising the fines content of the run-of-mine (ROM) coal offers numerous savings and benefits.

Here are a few facts to consider:
The cost of washing coal fines is higher because of the processes used and the product losses that occur (resulting in lower recovery).
With increased losses, more tailings have to be disposed in a suitable facility.
Coal that does not meet the customer’s size requirements cannot be sold.
A lower level of fines in the ROM results in a lower level of respirable and airborne dust, increasing workplace safety and reducing the risk of coal dust explosions.
Coal fines have the tendency to retain moisture, which causes disadvantages in the downstream processes.

The breakage of coal occurs throughout the process chain, from extraction at the face to the point where it is used. Some of this breakage is intentional, e.g., extraction and crushing, and some is unwanted, occurring when the coal is transported, stockpiled, sized or washed. Generally, breakage behaviour greatly depends on the geology, but mining technology offers a chance to affect the amount of fines generated along the process chain. It is of the utmost importance to use this chance and reduce the level of fines to the greatest possible extent.

Wirtgen has conducted several large-scale field tests on material degradation recently. It was found that Wirtgen surface miners offer significant advantages when it comes to the reduction of fines.

Wirtgen surface miners
A Wirtgen surface miner is a crawler-mounted mining machine with a rotating cutting drum for rock penetration mounted at the centre of gravity. This ensures that the full machine weight of the miner can be transformed into rock penetration force. The cutting drum transfers the material onto a conveyor belt (Figure 1) from which it is directly loaded onto a dump truck.

The surface miner mines layer by individual layer down to the designated depth. The cutting depth can vary according to the seam thickness. Even thin seams ‘ just 10 cm thick ‘ can be mined and precisely separated from the inter-burden layers above and below it. This makes for a selective, cost-effective and eco-friendly mining of mineral deposits with a high degree of purity GCo without drilling and blasting.

PSD field tests
In recent years, Wirtgen has conducted several large-scale field tests on particle size distribution and material degradation. Coal and sedimentary ore from eight different pits were analysed to obtain their particle size distribution. Almost 8,000 tonnes of material were screened to compare the material produced by surface miners and conventional mining methods.

In one coal mine, Wirtgen surface miners are operating alongside dozers that employ the conventional rip-and-stack method. In view of the current coal prices, the mine was optimising every step of the operation. This included optimising the process for target size material, enabling most of the material to be processed in the cheaper coarse circuit of the processing plant. They were also keen on reducing crushing costs. Table 1 shows the plant’s feed size requirements.

The test proved the suitability of the surface miner for this kind of operation once more. The machine delivered coal with a lower fines level and more target size material than the conventional dozer rip-and-stack method (Figure 2). In fact, out of the 1,500 t/h of coal delivered from the dozer to the processing plant, 225 t/h are fines < 2 mm. With the surface miner, it will only be 185 t/h. This means that 22 per cent less coal has to be washed in the fines circuit and can be washed in the cheaper coarse circuit. Looking at the material < 1 mm, the plant even has to process 33 per cent less fine material when working with surface miner coal.

The surface miner delivers more than 70 per cent target size coal (2-40 mm), while the dozer ranges at less than 58 per cent. Additionally, savings are generated in the crushing stage: only 17 per cent of the material coming from the surface miner has to be crushed, as opposed to more than 26 per cent when processing dozer coal. This will also result in more fines that have to be processed.

Another trial location was a sedimentary ore deposit that is mined using surface miners and the conventional drill-and-blast method. There, the surface miner was able to continually feed material with a < 1 mm fines level as low as 15 per cent to the processing plant. The normal plant feed (includes material of drill-and-blast and surface miner operation) contained 25 per cent and more fines < 1 mm.

Impact of rehandling
Rehandling contributes significantly to the material degradation occurring during the mining process. Simulating the rehandling of material, Wirtgen conducted a study to establish the amount of material degradation that does occur. For simulation purposes, 80 tonnes of material were loaded by a wheel loader and run through a screening plant several times. With every throughput, the amount of fine material increased significantly. During five test cycles in coal, the amount of material < 4 mm increased from 19 per cent to 26 per cent, representing an increase of 34 per cent. A similar result was found with sedimentary ore: the fine fraction increased by 24 per cent during five test cycles (Figure 3).

None of the steps in this rehandling simulation (loading, transport to the screen deck, sizing on the screen deck itself) involves the high material stress levels that would be induced, for example, by a dozer moving on stockpiled material. Nevertheless, significant material degradation was measured during the simulation. One can assume that the material degradation that takes place during stockpiling results in an even higher increase of the fine fractions.

Keeping in mind that even this kind of ‘soft’ rehandling causes significant material degradation and that a lot of rehandling steps occur all along the mining process, it is important to minimise the number of rehandling steps. What is more, every rehandling step itself results in additional costs. This is where Wirtgen surface miners offer a two-fold advantage: material mined with a surface miner has not been blasted, but cut out of the ground by the rotating cutting drum, thus the level of fines is already low. But as the material is loaded straight onto a truck, rehandling is kept to a minimum and thus the level of fines stays as low as possible.

Looking at the complete mining operation, using a surface miner simplifies mining operation and reduces the number of process steps (Figure 4), resulting in immediate cost savings.

Summary
High levels of coal fines in the ROM material result in higher costs for washing, lower recovery, reduced workplace safety and negative impacts on the downstream processes. Knowing where these coal fines come from and optimising the procedures along the process chain can yield significant savings. Wirtgen has conducted several studies to address the fines problem and proved that it is possible to reduce the level of coal fines in the ROM. Mining coal with a Wirtgen surface miner is a first step toward substantial savings in the process chain.

Additionally, operating a Wirtgen surface miner will reduce the quantity of active equipment required to load one tonne of coal by streamlining the mining process. Furthermore, it will simplify the interdependence of process steps in the mining operation, reducing costly time losses between the individual process steps.

For further information please contact: e-mail: presse@wirtgen.com, www.wirtgen.com

Process

Price hikes, drop in input costs help cement industry to post positive margins: Care Ratings

Published

3 years ago

October 21, 2021

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Region-wise,the southern region comprises 35% of the total cement capacity, followed by thenorthern, eastern, western and central region comprising 20%, 18%, 14% and 13%of the capacity, respectively.

The cement industry is expected to post positive margins on decent price hikes over the months, falling raw material prices and marked drop in overall production costs, said an analysis of Care Ratings.

Wholesale and retail prices of cement have increased 11.9% and 12.4%, respectively, in the current financial year. As whole prices have remained elevated in most of the markets in the months of FY20, against the corresponding period of the previous year.

Similarly, electricity and fuel cost have declined 11.9% during 9M FY20 due to drop in crude oil prices. Logistics costs, the biggest cost for cement industry, has also dropped 7.7% (selling and distribution) as the Railways extended the benefit of exemption from busy season surcharge. Moreover, the cost of raw materials, too, declined 5.1% given the price of limestone had fallen 11.3% in the same aforementioned period, the analysis said.

According to Care Ratings, though the overall sales revenue has increased only 1.3%, against 16% growth in the year-ago period, the overall expenditure has declined 3.2% which has benefited the industry largely given the moderation in sales.

Even though FY20 has been subdued in terms of production and demand, the fall in cost of production has still supported the cement industry by clocking in positive margins, the rating agency said.

Cement demand is closely linked to the overall economic growth, particularly the housing and infrastructure sector. The cement sector will be seeing a sharp growth in volumes mainly due to increasing demand from affordable housing and other government infrastructure projects like roads, metros, airports, irrigation.

The government’s newly introduced National Infrastructure Pipeline (NIP), with its target of becoming a $5-trillion economy by 2025, is a detailed road map focused on economic revival through infrastructure development.

The NIP covers a gamut of sectors; rural and urban infrastructure and entails investments of Rs.102 lakh crore to be undertaken by the central government, state governments and the private sector. Of the total projects of the NIP, 42% are under implementation while 19% are under development, 31% are at the conceptual stage and 8% are yet to be classified.

The sectors that will be of focus will be roads, railways, power (renewable and conventional), irrigation and urban infrastructure. These sectors together account for 79% of the proposed investments in six years to 2025. Given the government’s thrust on infrastructure creation, it is likely to benefit the cement industry going forward.

Similarly, the Pradhan Mantri Awaas Yojana, aimed at providing affordable housing, will be a strong driver to lift cement demand. Prices have started correcting Q4 FY20 onwards due to revival in demand of the commodity, the agency said in its analysis.

Industry’s sales revenue has grown at a CAGR of 7.3% during FY15-19 but has grown only 1.3% in the current financial year. Tepid demand throughout the country in the first half of the year has led to the contraction of sales revenue. Fall in the total expenditure of cement firms had aided in improving the operating profit and net profit margins of the industry (OPM was 15.2 during 9M FY19 and NPM was 3.1 during 9M FY19). Interest coverage ratio, too, has improved on an overall basis (ICR was 3.3 during 9M FY19).

According to Cement Manufacturers Association, India accounts for over 8% of the overall global installed capacity. Region-wise, the southern region comprises 35% of the total cement capacity, followed by the northern, eastern, western and central region comprising 20%, 18%, 14% and 13% of the capacity, respectively.

Installed capacity of domestic cement makers has increased at a CAGR of 4.9% during FY16-20. Manufacturers have been able to maintain a capacity utilisation rate above 65% in the past quinquennium. In the current financial year due to the prolonged rains in many parts of the country, the capacity utilisation rate has fallen from 70% during FY19 to 66% currently (YTD).

Source:moneycontrol.com

Process

Wonder Cement shows journey of cement with new campaign

Published

3 years ago

October 21, 2021

admin

The campaign also marks Wonder Cement being the first ever cement brand to enter the world of IGTV…

ETBrandEquity

Cement manufacturing company Wonder Cement, has announced the launch of a digital campaign ‘Har Raah Mein Wonder Hai’. The campaign has been designed specifically to run on platforms such as Instagram, Facebook and YouTube.

#HarRaahMeinWonderHai is a one-minute video, designed and conceptualised by its digital media partner Triature Digital Marketing and Technologies Pvt Ltd. The entire journey of the cement brand from leaving the factory, going through various weather conditions and witnessing the beauty of nature and wonders through the way until it reaches the destination i.e., to the consumer is very intriguing and the brand has tried to showcase the same with the film.

Sanjay Joshi, executive director, Wonder Cement, said, "Cement as a product poses a unique marketing challenge. Most consumers will build their homes once and therefore buy cement once in a lifetime. It is critical for a cement company to connect with their consumers emotionally. As a part of our communication strategy, it is our endeavor to reach out to a large audience of this country through digital. Wonder Cement always a pioneer in digital, with the launch of our IGTV campaign #HarRahMeinWonderHai, is the first brand in the cement category to venture into this space. Through this campaign, we have captured the emotional journey of a cement bag through its own perspective and depicted what it takes to lay the foundation of one’s dreams and turn them into reality."

The story begins with a family performing the bhoomi poojan of their new plot. It is the place where they are investing their life-long earnings; and planning to build a dream house for the family and children. The family believes in the tradition of having a ‘perfect shuruaat’ (perfect beginning) for their future dream house. The video later highlights the process of construction and in sequence it is emphasising the value of ‘Perfect Shuruaat’ through the eyes of a cement bag.

Tarun Singh Chauhan, management advisor and brand consultant, Wonder Cement, said, "Our objective with this campaign was to show that the cement produced at the Wonder Cement plant speaks for itself, its quality, trust and most of all perfection. The only way this was possible was to take the perspective of a cement bag and showing its journey of perfection from beginning till the end."

According to the company, the campaign also marks Wonder Cement being the first ever cement brand to enter the world of IGTV. No other brand in this category has created content specific to the platform.

Process

In spite of company’s optimism, demand weakness in cement is seen in the 4% y-o-y drop in sales volume. (Reuters)

Published

3 years ago

October 21, 2021

admin

Cost cuts and better realizations save? the ?day ?for ?UltraTech Cement, Updated: 27 Jan 2020, Vatsala Kamat from Live Mint

Lower cost of energy and logistics helped Ebitda per tonne rise by about 29% in Q3
Premiumization of acquired brands, synergistic?operations hold promise for future profit growth Topics

UltraTech Cement
India’s largest cement producer UltraTech Cement Ltd turned out a bittersweet show in the December quarter. A sharp drop in fuel costs and higher realizations helped drive profit growth. But the inherent demand weakness was evident in the sales volumes drop during the quarter.

Better realizations during the December quarter, in spite of the 4% year-on-year volume decline, minimized the pain. Net stand-alone revenue fell by 2.6% to ?9,981.8 crore.

But as pointed out earlier, lower costs on most fronts helped profitability. The chart alongside shows the sharp drop in energy costs led by lower petcoke prices, lower fuel consumption and higher use of green power. Logistics costs, too, fell due to lower railway freight charges and synergies from the acquired assets. These savings helped offset the increase in raw material costs.

The upshot: Q3 Ebitda (earnings before interest, tax, depreciation and amortization) of about ?990 per tonne was 29% higher from a year ago. The jump in profit on a per tonne basis was more or less along expected lines, given the increase in realizations. "Besides, the reduction in net debt by about ?2,000 crore is a key positive," said Binod Modi, analyst at Reliance Securities Ltd.

Graphic by Santosh Sharma/Mint
What also impressed analysts is the nimble-footed integration of the recently merged cement assets of Nathdwara and Century, which was a concern on the Street.

Kunal Shah, analyst (institutional equities) at Yes Securities (India) Ltd, said: "The company has proved its ability of asset integration. Century’s cement assets were ramped up to 79% capacity utilization in December, even as they operated Nathdwara generating an Ebitda of ?1,500 per tonne."

Looks like the demand weakness mirrored in weak sales during the quarter was masked by the deft integration and synergies derived from these acquired assets. This drove UltraTech’s stock up by 2.6% to ?4,643 after the Q3 results were declared on Friday.

Brand transition from Century to UltraTech, which is 55% complete, is likely to touch 80% by September 2020. A report by Jefferies India Pvt. Ltd highlights that the Ebitda per tonne for premium brands is about ?5-10 higher per bag than the average (A cement bag weighs 50kg). Of course, with competition increasing in the arena, it remains to be seen how brand premiumization in the cement industry will pan out. UltraTech Cement scores well among peers here.

However, there are road bumps ahead for the cement sector and for UltraTech. Falling gross domestic product growth, fiscal slippages and lower budgetary allocation to infrastructure sector are making industry houses jittery on growth. Although UltraTech’s management is confident that cement demand is looking up, sustainability and pricing power remains a worry for the near term.