Concrete

Grinding: Smarter Solutions

Published

4 years ago

August 10, 2022

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Grinding might be an individual step in the cement production line but it is a crucial one, given the energy consumption and impact on the quality of output that it gives. ICR explores how grinding methods have evolved with the help of technology and with the use of modern-age grinding aids.

Grinding in the cement manufacturing process takes place at three stages: raw meal grinding, cement grinding, and raw coal grinding. The process mainly includes the mixed materials crushing, material batching, pre-grinding, fine grinding, powder classification, dust collecting, automatic control, and other technologies, making cement production high yield and high quality, in line with the requirements of energy-saving and emission reduction.
According to an article published in Journal of Materials Research and Technology, Volume 9, Issue 4, 2020, Grinding is a central process in mineral processing to achieve particle size reduction and mineral liberation, and is highly energy-intensive. It accounts for 50 per cent of power consumption in a concentrator. In general, grinding has poor energy efficiency and accounts for about 2 per cent to 3 per cent of the world’s generated electricity. Due to the depleting resources, the processing of refractory ores is becoming common. Such processes require fine grinding or ultrafine grinding to liberate the valuable minerals from gangue material; thus, energy-efficient technologies and strategies are required.

Post clinkerisation of raw material, the clinker is extracted from the tank and transported to the cement mill hopper by belt conveyors. A measured quantity of clinker and gypsum is fed into our closed-circuit ball mill which incorporates a high-efficiency separator. At this stage, the type of cement can be differentiated. For example, OPC is produced by the inter-grinding and blending of 95 per cent clinker with 5 per cent gypsum to a fineness of 280 sq m per kg. PPC is produced by the inter-grinding and blending of 65 per cent clinker with 30 per cent fly ash and 5 per cent gypsum to a fineness of 320 sq m per kg. Where, fineness is a controlled parameter for cement to ensure better hydration and strength development. Ground cement is then stored in a water-proof concrete silo for packing.
The cement grinding station is an individual step in the cement production line. The new-age cement grinding units adopt pre-grinding technology. It not only reduces the particles of feeding materials, but also helps to produce cracks and flaws inside the particles, which largely increase the production capacity of cement mill, reduce the energy consumption. Cement grinding station can greatly digest the slag, fly ash, slag, coal gangue and other industrial waste residues near the city, is a green industry.

Evolution of cement grinding technology
A cement mill is the equipment used to grind the hard, nodular clinker from the cement kiln into the fine grey powder that is cement. Historically, the hydraulic cements were known to be relatively soft and could be readily ground with the primitive technology of the day, using flat millstones. The emergence of Portland cement in the 1840s made grinding considerably more difficult, because the clinker produced by the kiln is often as hard as the millstone material. Because of this, cement continued to be ground very coarsely (typically 20 per cent over 100 μm particle diameter) until better grinding technology became available.
The year 1885 saw the development of specialised steel that led to the development of new forms of grinding equipment. With this the cement grinding became finer with time and advancement of technology and equipment. The progressive reduction in the proportion of larger, un-reactive cement particles has been partially responsible for the fourfold
increase in the strength of Portland cement during the twentieth century.
The principle of Grate Discharge grinding is nearly universally adapted in the cement grinding industry. Grate Discharge Ball Mills are the rule rather than the exception. Rod Mills for raw and finished grinding began to enter the picture. Larger and larger diameter mills have become common. Lengths tend to shorten.
Raw Cement Grinding: This phase may be a wet or dry grinding phase, the end product of it goes to the kiln. Typically, the materials ground includes limestone cement rock, marl or marine shells along with secondary materials like shale or clay. A typical raw mix consists of 75 per cent to 85 per cent limestone, 12 per cent to 25 per cent shale, and the balance materials in this mix consist of silica or quartzite and iron oxide. Exact proportioning of the same depends upon their chemical properties before and after calcining to cement clinker.
During the wet grinding of raw materials, a thorough mixing takes place during comminution, making the process more efficient and permitting a balanced feed direct to the grinding mill. Another pro of this process is the elimination of the dust hazard and cleaner plants. Theories suggest that where low cost fuel is available, the extra heat required during calcining, to drive off water in the process, is actually less costly than resorting to less efficient dry grinding. Improvements in air separators and more efficient dust collecting systems have minimised some of these problems to a point where present day costs become closely parallel.
Anirudh Dani, Grinding Unit Head, JK Cement Works, says, “Major key technical functionalities are production capacity, cement grade, special energy consumption, maintenance cost, construction cost etc., for the installation of the grinding unit. Further, major key strategic deciding factors are land availability, market demand, logistics optimisation, geographical analysis, raw material availability etc., for the finalisation of the cement grinding location.”

“Cement grinding cost is 40 to 45 per cent of variable cost of cement production. By effective control measures and minuscule innovations, we can achieve a significant impact on profit maximisation with environmental sustainability,” he adds.

Cement Grinding Machines
Equipment required for the cement grinding plant include cement roller press, cement silos, belt conveyors, cement mills, classifiers, bucket elevators, packing machines, etc. The grinding mill and cement roller press are the core equipment of the cement grinding units. These grinding mills directly decide the quality and cost of whole cement grinding unknit. There are three common solutions for cement grinding plants: cement roller press and ball mill, closed-circuit cement mill, and cement crusher and ball mill.
In the cement roller press and ball mill system, the ground materials from the roller press are first processed by the separator and divided into two parts: the coarse part and the fine part. The fine part is sent to the ball mill and ground to produce cement, the coarse part is returned to the roller press to be ground again. The finished product cement from this system also has wide particle size distribution and stable performance. With the invention of the V-type separator, the combined grinding system composed of roller press and ball mill has been developed to further reduce the energy consumption of the cement grinding process. This system is considered efficient and productive for the cement manufacturing process.
Cement grinding is a flexible and generally intermittent operation. With mills that have sufficient capacity to grind the clinker considerably faster than kilns produce, this allows them to meet the maximum demands when necessary: at other times, they can be run at a capacity less than full or they can be stopped completely.
Considering the consumption of energy, mills are known to have a capacity greater than that of clinker production, thus grinding can be done during periods that offer the most favourable energy rates. The power supply and charges vary from plant to plant and also the arrangements for programming the grinding.
Grinding can be either ‘open circuit’ or ‘closed circuit’. In an open-circuit system, the feed of incoming clinker is adjusted in such a way that it achieves the desired fineness of the product. In the present day, open circuits have become obsolete. However, in a closed-circuit system, coarse particles are separated from the finer product in a separator and then brought back to a mill for further grinding. Energy consumption, during grinding operation, whether raw material or finished products, is of paramount importance. Therefore, any innovation to reduce energy consumption is always watched closely not only in India but across the globe. Power generation, distribution and consumption are focused areas to many current world issues, controlling the industry’s energy usage is a matter of interest to different federal governments across the globe.

Grinding Aids for Cement
Cement grinding aids are added to the clinker during the grinding process for the prime reason of eliminating the coating effect of the clinker on grinding mill walls and to increase the production rate of cement keeping the surface area constant. They also allow cement to be transported in delivery trucks and storage in silos without lump formation. However, cement grinding aids also determine and improve the clinker grinding efficiency, power flowability, and strength development of binders. They also impact the mechanical properties of cement in a positive manner, such as, setting time, compressive strength, surface area, and mortar workability. The principal application of cement grinding aids concerns with the mill output and dry cement handling.
The demand for cement in the current day and age of urbanisation and industrialisation is growing steadily. Selection of cement for these purposes is mainly dependent on efficiency and low cost. Cement grinding aids are used to improve the efficiency of cement production and reduce energy consumption and current consumers of cement are making their choices of buying cement on these factors and grinding aids play a key role in determining the same.

Looking Ahead
According to a report by IMARC, the global cement grinding aid and performance enhancers market is expected to exhibit a CAGR of 3.68 per cent during 2022-2027.
Over the last few decades, in order to address the high energy consumption and scarcity of potable water for mineral processing, chemical additives or grinding aids have become a promising alternative in the cement manufacturing process. Also, studying the effect of grinding aids on size reduction units is crucial for the beneficiation value chain of minerals and the impact on downstream processes.
Grinding aids range from organic to inorganic chemicals. For example, organic chemicals include, polyols, alcohols, esters, amines, while, inorganic chemicals include, calcium oxide, sodium silicate, sodium carbonate, sodium chloride etc. The process of grinding cement is required to be efficient and productive. Grinding aids are added to support the same. Grinding efficiency is mainly evaluated based on energy consumed per given mass of material as a function of time. A study on these materials shows reduction in the energy consumption increases by increasing grinding aid dosage to a maximum, after which further addition gives no effect.
Vimal Jain, Director – Technical, Heidelberg Cement India Ltd., says, “Approximately 60 per cent of the consumed power of the whole process is absorbed in the grinding process. To be competitive in the market it is mandatory for any organisation to have a minimum power consumption. This would mean accordingly minimising our input cost.”
“Some of the older technology and older design of the mills used upto 45 units of energy per tonne of cement, but with the advancement of technology, the energy consumption is significantly reduced, thus reducing the cost for the same. This energy saving or reduction in use directly contributes to the profitability of the process,” he adds.
Energy conservation and reducing carbon emission are the primary motives of every cement making organisation. Grinding units are energy intensive sections of the manufacturing process, thus, need to be looked at with advanced technological support as well as material support with grinding aids. Continuous research and development is the solution to find newer materials that will help make the grinding process more productive and efficient, while simplifying the application and functionality for all those involved.

-Kanika Mathur

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Concrete

CarbonStrong Raises Rs 125 Million To Scale Low Carbon Cement Tech

To build capacity of 100,000 tonnes a year

Published

1 day ago

August 28, 2026

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CarbonStrong has raised Rs 125 million (125 mn) to scale a low carbon cement technology and build commercial production capacity. The startup was founded in 2022 by Harsh Jain and Vikramaditya Singh and has moved from customer trials to plans for industrial supply. The company said its material replaces up to 50 per cent of cement in concrete while reducing costs and improving durability.

CarbonStrong states the product is around 30 per cent cheaper than cement and compatible with existing concrete plants, reducing the need for new equipment and operational disruption. Trials and paid pilots have been conducted in Bengaluru, Hyderabad and Chennai with demonstration projects involving ready-mix firms and precast manufacturers. Compatibility with current workflows forms a central part of the commercial strategy, aiming to ease adoption by builders and contractors.

The funding will support construction of a facility with capacity of up to 100,000 tonnes (100,000 t) a year over the next two years to supply early customers commercially. The firm is also developing materials from steel slag, copper slag and mine tailings to expand its feedstock base, while noting the technical challenge of homogenising different waste streams. Recognition by HCL ClimaForce in 2026 and by the Avaana-Startup India-NITI Aayog AIM Grand Challenge in 2025 has underscored progress.

Industry adoption remains the principal test and will require consistent material performance, supply reliability and competitive economics. CarbonStrong projects the Indian market for cement substitutes could reach Rs 250 billion (250 bn) by 2030 and has set an ambition to produce 10 million tonnes a year by 2035 (10 mn t), a target far above its near term capacity. Moving from pilots to production demands capital, manufacturing discipline and customers willing to specify the material beyond demonstrations. The recent Rs 125 million raise is intended to fund the next phase of scale and to demonstrate that industrial waste can become a dependable input for lower carbon construction.

Concrete

Protect Your Margins

Published

1 day ago

August 28, 2026

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In a research-backed article, Dr SB Hegde examines why carbon-adjusted profitability and LC3 will decide the next set of winners in cement manufacturing.

The Indian cement industry has achieved world-class operational efficiency through lower specific energy consumption, high plant utilisation and a reduced average clinker factor of approximately 67.5 per cent. These traditional measures of operational excellence remain essential. However, they are no longer sufficient. Carbon now carries a measurable financial cost under India’s Carbon Credit Trading Scheme (CCTS) and under European carbon markets. Future leadership will be defined by carbon-adjusted profitability, the ability to generate strong returns while systematically lowering the carbon intensity of every ton sold.
Limestone calcined clay cement (LC3) offers a practical, scalable pathway to achieve this dual objective. By replacing up to 50 per cent of clinker with calcined clay and limestone, LC3 can reduce CO2 emissions by 30–40 per cent while delivering comparable or superior durability performance.
This article examines the technical foundations of LC3, European industrial practices, the emerging Indian carbon market and a concrete roadmap for Indian companies to embed carbon-adjusted metrics and LC3 into daily operations, incentives and commercial strategy.

Limits of traditional operational excellence
For many years, plant performance has been judged primarily by five indicators: specific heat consumption, specific power consumption, kiln and mill utilisation, clinker factor and overall equipment effectiveness. These metrics drove continuous improvement and helped the industry reduce energy use and increase the share of blended cement. Three structural changes have rendered them incomplete as sole measures of success.
First, carbon now carries a real or opportunity cost. Plants that improve volume or lower cash cost while raising or stagnating emissions intensity create a hidden liability that will surface as CCTS trading matures and as green procurement expands.
Second, lower-carbon products such as LC3 and high-performance blended cements are creating differentiated market segments. Customers in infrastructure, real estate and export-oriented construction are beginning to specify embodied-carbon limits.
Third, investors and lenders increasingly treat carbon intensity as a financial risk factor. Traditional KPIs can mask the divergence between short-term cash profit and long-term carbon-adjusted value.

What is carbon-adjusted profitability?
Carbon-adjusted profitability evaluates normal profit after explicit adjustment for carbon performance. A practical expression is:
Carbon-Adjusted EBITDA = Conventional EBITDA – Carbon Cost + Green Premium Income
Carbon cost may be an internal carbon price, the actual cost of purchasing Carbon Credit Certificates under CCTS, or the opportunity cost of high emissions relative to peers. Green premium income arises when customers pay more for verified lower-carbon cement or when the company sells surplus credits. Tracking both conventional and carbon-adjusted profit side-by-side gives management a clearer picture of value creation under evolving market rules.

Table 1. Traditional KPIs versus Carbon-Adjusted Leadership Metrics
Traditional Focus New Leadership Metric Why It Matters
Specific energy consumption Emissions intensity (kg CO2/t cement) Directly linked to future CCTS and CBAM costs
Kiln utilisation Carbon-adjusted contribution margin Reveals true value of incremental volume
Clinker factor Share of lower-carbon products sold (incl. LC3) Measures commercial success of the transition
Power cost per tonne Effective carbon cost per tonne sold Expose hidden liabilities
Absolute EBITDA Carbon-adjusted EBITDA + green premium Aligning profit with future market reality

LC3: Technical foundations and performance advantages
LC3 is a ternary blended cement that typically combines approximately 50 per cent clinker, 30 per cent calcined clay, 15 per cent limestone and 5 per cent gypsum (the classic LC3-50 formulation). The decisive technical advantage is that clay is calcined at 700–850 °C, far below the 1,450 °C required for clinker production. This lower temperature, together with the substantial reduction in clinker content, delivers CO2 reductions of 30–40 per cent relative to ordinary Portland cement (OPC).
Chemistry is synergistic. Calcined kaolinitic clay (metakaolin) reacts with calcium hydroxide from clinker hydration and with limestone to form additional C-A-S-H gel and carboaluminate phases. These phases densify the microstructure, reduce porosity and improve durability.
Field experience shows superior resistance to chloride ingress, sulphate attack and alkali–silica reaction. Early-age strength can match OPC with high-reactivity clays; later-age strengths routinely meet 42.5 and 52.5 grade requirements.
Importantly, LC3 does not require high-purity kaolin. Clays with 40 per cent or even lower kaolinite content can be activated successfully, expanding raw-material availability across India. Calcination can use adapted rotary kilns or dedicated flash calciners, making the technology compatible with existing plant infrastructure and far less capital-intensive than carbon capture.
Economic analyses show that LC3 can be produced at equal or lower cost than OPC in many locations because of reduced energy demand and cheaper clay. Life-cycle assessments consistently report 30–40 per cent lower embodied CO2 per tonne of cement.
Table 2. Comparative profile: OPC versus LC3-50
Parameter OPC LC3-50
Typical clinker content ~95 per cent ~50 per cent
CO2 emissions (relative) Baseline (≈0.85 t CO2/t cement process + fuel) 30–40 per cent lower
Clay calcination temperature Not applicable 700–850 °C
Key hydration products C-S-H, portlandite, ettringite C-A-S-H + carboaluminates
Chloride & sulphate resistance Good Superior
Production cost potential Baseline Equal or lower in most locations
Infrastructure compatibility Existing High (minor adaptations)

In India, commercial adoption has begun in earnest. JK Cement commenced the first commercial production of LC3 in the Indian subcontinent at its Mangrol plant in Rajasthan in 2025 under BIS standard IS 18189.
By early 2026, approximately 2,000 tonnes had been produced and sold, avoiding an estimated 500 tonnes of CO2. JK Lakshmi Cement followed with commercial launch of its Green PRO LC3 grade from the Jaykaypuram plant. As of mid-2026, two producers are supplying LC3 to the market. The first large-scale infrastructure application is the Noida International Airport (Jewar), where LC3 was used in the runway and a building complex, demonstrating full constructability and performance under demanding conditions. These early volumes are still small relative to national cement demand, but they mark the critical transition from pilot to commercial reality. Companies that scale capacity now will be positioned to capture both CCTS credits and emerging green-procurement demand.

Why the shift is accelerating
According to the World Bank’s State and Trends of Carbon Pricing 2026, direct carbon pricing now covers nearly 30 per cent of global greenhouse-gas emissions and generated more than US$107 billion in public revenue in 2025. The average global carbon price stands at approximately US$21 per tonne, although regional prices vary widely.
In Europe, the EU ETS price has traded near €80–85 per tonen in mid-2026. Free allocation for cement is being withdrawn in parallel with CBAM. European producers therefore face a clear signal: every tonne of avoided CO2 improves both compliance and competitiveness. Holcim has scaled calcined-clay production, including Europe’s first dedicated line at Saint-Pierre-la-Cour (France) and a second line in the Czech Republic (2026). Heidelberg Materials, Cementir (FUTURECEM) and others have commercialised low-clinker calcined-clay blends across multiple markets, showing that carbon-adjusted profitability is already reshaping capital allocation in the world’s most mature carbon market.India’s CCTS is now operational. Binding emission intensity targets apply to 186 cement facilities for FY 2025–26 and FY 2026–27. Average required reductions for integrated plants are modest (around 2.7 per cent by FY 2027), yet the direction is clear.
Trading of Carbon Credit Certificates is expected in the second half of 2026, with early prices likely in the `800–1,500 per tonne range. Plants that outperform targets can sell credits; those that underperform must buy them or face compensation. Cement is well positioned to be a net supplier of credits if clinker factor continues to fall through LC3 and other low-clinker systems.

Way forward for India
India starts from a strong baseline, world-class energy efficiency and a clinker factor already lower than the global average. The next competitive frontier is the deliberate reduction of process emissions through clinker substitution at scale. LC3 is uniquely suited to Indian conditions because suitable clays are widely distributed, the technology fits existing kiln and grinding infrastructure, and the resulting product can meet the performance demands of both infrastructure and building construction.
A practical national pathway contains five interlocking elements:

Standards and acceptance: Accelerated finalisation and promotion of BIS specifications for calcined-clay and limestone–calcined-clay cements will remove a key barrier to commercial uptake. Alignment with European practice (EN 197-5) can facilitate knowledge transfer and export readiness.
Supply-chain development: Investment in flash calcination capacity and systematic characterisation of regional clay deposits will secure reliable, low-cost feedstock. Existing rotary kilns can be adapted for initial volumes while dedicated calciners are built.
Incentive alignment: Part of variable compensation for plant managers, sales teams and senior leadership should be linked to emissions intensity reduction and to the volume of lower-carbon products (including LC3) sold. Without this link, traditional volume and cost targets will continue to dominate behaviour.
Product-level carbon accounting: Reliable measurement of emissions intensity at the individual cement grade level, supported by third-party verification where required, is essential for both CCTS compliance and credible green claims.
Demand-side pull: Green public procurement policies that specify maximum embodied-carbon thresholds for major infrastructure projects will create a predictable market for LC3 and other low-carbon cements, accelerating scale and cost reduction.
Companies that treat LC3 as a strategic product line rather than a niche offering will be better positioned to generate surplus Carbon Credit Certificates, capture any emerging green premium, and protect margins as carbon costs rise.

Organisational changes required
Technical capability alone is insufficient. Three organisational shifts are required.
Daily management: Emissions intensity must appear on the same daily and monthly dashboards as heat consumption, power consumption and utilization. Plant reviews should examine both conventional and carbon-adjusted results.
Incentives: A meaningful portion of bonuses for plant heads, technical teams and sales leadership should be tied to lower emissions intensity and successful commercialisation of LC3 and other low-carbon grades.
Commercial approach: Sales teams need clear volume and pricing targets for lower-carbon products, supported by technical service that helps customers specify and place the material correctly. Without commercial pull, excellent technical performance remains under-utilised.

Table 3. Three-stage roadmap to carbon-adjusted profitability
Time Horizon Priority Actions Expected Outcome
Next 12 months Add emissions intensity to plant dashboards; establish internal carbon price; initiate LC3 pilot production and customer trials Visibility and early organisational learning
12–24 months Revise incentive systems; scale LC3 and other low-carbon grades to key accounts; secure third-party verification capability People and sales aligned with carbon goals
24–36 months Embed carbon-adjusted metrics in board reporting and capital allocation; expand calcined-clay capacity Full system integration and competitive advantage

Questions senior leaders should ask
Boards can accelerate the transition by insisting on answers to a short list of questions:
• Is our carbon-adjusted profit improving, stable or declining relative to conventional EBITDA?
• Did recent volume growth improve or worsen our emissions intensity?
• What share of sales already comes from lower-carbon products, including LC3, and what is the trajectory?
• How exposed is our capital expenditure plan to rising carbon costs under CCTS and potential CBAM-related requirements?
• Do our incentive systems still reward only volume and cost, or have they been updated to include carbon performance?
Treating carbon with the same seriousness as energy cost or kiln utilization does not diminish operational excellence; it expands the definition of excellence to match the new competitive reality.

Looking ahead
By 2030 the gap between leading and lagging cement companies will not be decided by who records the lowest specific heat consumption. It will be decided by who delivers the strongest carbon-adjusted profits.
Absolute emissions may still rise as national production grows. That is not the issue. Companies that reduce intensity year after year and successfully sell cleaner products will pull ahead in both domestic and export markets. Those that do not will fall behind, even if their traditional efficiency numbers look strong.
Operational excellence built the Indian cement industry. It remains the foundation. It is no longer the complete picture. Carbon-adjusted profitability is the clearer measure of success.
LC3 is not a distant technology. It is available now. It cuts CO3 by 30–40 per cent, works with existing plants, and is already in commercial production in India. Companies that treat it as a strategic product, not a pilot, will protect their margins and generate tradable credits.
Leaders who act now will place carbon metrics on daily dashboards, link incentives to intensity reduction and LC3 sales, invest in calcined-clay capacity, and build commercial capability to sell lower-carbon products. They will shape the next chapter of the industry.

References

World Bank. (2026). State and Trends of Carbon Pricing 2026. Washington, DC: World Bank Group.
International Carbon Action Partnership (ICAP). (2026). India Carbon Credit Trading Scheme – Status and Coverage. Berlin: ICAP.
Ministry of Environment, Forest and Climate Change / Bureau of Energy Efficiency. (2025). Greenhouse Gases Emission Intensity Target Rules, 2025. New Delhi: Government of India.
Scrivener, K., Martirena, F., Bishnoi, S., & Maity, S. (2018). Calcined clay limestone cements (LC3). Cement and Concrete Research, 114, 49–56.
RMI. (2024). The Business Case for LC3. Rocky Mountain Institute.
European Commission. (2026). EU Emissions Trading System – Allowance Price Data and Free Allocation Phase-out Schedule. Brussels.
Holcim. (2025–2026). Scaling Calcined Clay for Sustainable Building – Corporate Updates on European and Latin American Capacity. Zurich: Holcim Ltd.
LC3 Project / EPFL. (2026). LC3 – A Guide to Best Practices for Scalable, Affordable and Sustainable Low-Carbon Building. Lausanne: École Polytechnique Fédérale de Lausanne.
Business Today / Industry Reports. (2026). First Large-Scale LC3 Application at Noida International Airport, Jewar. New Delhi.
NITI Aayog / Industry Analyses. (2026). Roadmap and Baseline Performance Indicators for the Indian Cement Sector. New Delhi.
Springer / Innovative Infrastructure Solutions. (2026). LC3 Systems: A Review of Chemistry, Performance, Durability and Sustainability toward Market Adoption.
Cementir Holding / Industry Sources. (2025–2026). FUTURECEM and Related Low-Clinker Technologies in Europe.
Climate Risk Horizons & Independent Analyses. (2026). Assessment of Emission Intensity Targets under India’s CCTS for Cement and Other Hard-to-Abate Sectors.
GCCA / TERI. (Various years). Decarbonization Roadmaps for the Indian Cement Industry.
EN 197-5:2021. Cement – Part 5: Portland-composite cement CEM II/C-M and Composite cement CEM VI. European Committee for Standardization.

Concrete

More Oversight Makes Cement Plants Less Safe

Published

1 day ago

August 28, 2026

admin

Dijam Panigrahi makes a counterintuitive but data-backed argument that routing every sensor alert through human approval does not make cement plants safer.

India’s cement industry has spent the last two years wiring kilns, mills and coolers with sensors and automated control systems, and the safety case for doing so is strong on paper. Contract workers still make up the majority of the industry’s workforce, and fatal accidents remain a recurring problem. The Indian National Cement Workers Federation has noted that around 83 per cent of workers in the sector hold precarious positions, a fact that resurfaced after an oxygen cylinder explosion killed three contract workers at a plant in Chhattisgarh.
Industry tallies compiled by IndustriALL found cement plants recorded at least seventeen accidents in one year with 21 workers killed, and ten accidents the following year with nine killed, most of them contract staff. Automated monitoring, in theory, closes that gap. A sensor never gets complacent and never skips a check because a shift is short staffed.
However, plants that respond by routing every anomaly reading to a person for approval are quietly building a system that fails the same way understaffing does. When operators receive dozens of flagged deviations a shift, most of them minor, they learn a simple lesson: the fastest way through the queue is to approve without reading closely. The safety benefit disappears, not because the technology failed, but because the humans supervising it adapted to the volume.

Why alerts get ignored
A study cited by manufacturing technology publisher Applied SmartFactory found more than 95 per cent of alarms in a semiconductor fab were low priority, and only about 4 per cent ever triggered an action, with just 100 out of 5,000 alarms accounting for 70 per cent of all alarm activity. The mechanism is the same whether the trigger is a vibration sensor or an AI model flagging a kiln temperature swing. Once the ratio of noise to signal crosses a threshold, workers stop treating the system as a decision aid and start treating it as a formality to clear.
The scale of AI deployment underway makes this more than a theoretical risk. Stanford’s 2026 AI Index Report found organisational adoption of AI has reached 88 per cent, even as documented AI incidents rose to 362 in 2025, up sharply from 233 the year before, according to analysis of the report. The Index also found only about a third of organisations have adopted a formal governance framework, with NIST’s AI Risk Management Framework cited by 33 per cent and ISO/IEC 42001 cited by 36 per cent.
Most manufacturers are deploying monitoring systems faster than they are building the judgment for when a flagged event actually needs a person’s attention. In India, plants run by JK Cement have begun pairing CCTV feeds with AI to define safe zones around heavy machinery, a promising direction that still depends on operators trusting and reading the alerts the system generates.

A three-tier model for cement plant
The fix is not less monitoring or more monitoring. It is classifying decisions by risk and by novelty, rather than treating human oversight as a single switch that is either on or off. A workable model sorts factory floor events into three tiers.
The first tier, proceed, covers deviations the plant has seen before that fall within known safe bounds, such as a kiln feed rate adjustment within an established range. These should run without a stop for approval, because routing them to a person only trains that person to click through.
The second tier, pause, covers events that are unusual but not yet dangerous, such as a vibration reading trending toward a limit or a fuel blend shifting outside its typical mix. These warrant a brief human check before the system proceeds, giving an operator the chance to apply judgment the model does not yet have.
The third tier, escalate, covers events that are both high risk and unfamiliar, such as a pressure reading combined with a temperature spike that has no close precedent in the plant’s history. These should stop the process entirely and require a decision from someone with the authority to shut down a line.

Who should set the threshold
Where these tiers get drawn matters as much as the framework itself. Threshold setting is frequently handed to the vendor supplying the monitoring software or to a plant’s IT department, both of which understand the technology but not the specific tolerances of a given kiln, mill or line. Operations staff, who know that a particular grinding unit runs hotter under monsoon humidity or that a calciner behaves differently after a refractory reline, are better positioned to calibrate what counts as routine on their own equipment.
Handing threshold ownership to operations does not remove IT or vendors from the process, but it puts the calibration decision closest to the people who live with its consequences on the floor.

Signals that oversight is actually working
A few concrete indicators reveal whether a monitoring setup is functioning as intended or simply providing the appearance of safety. The escalation rate over time is the first: a rate that stays flat or climbs slowly as operations mature is healthy, while one that spikes and then falls sharply often means operators have started overriding the system rather than engaging with it. Time to resolution is the second: escalations that take progressively longer to close suggest fatigue or confusion about ownership, not diligence. The third, and most telling, is how accurate the system’s own uncertainty estimates turn out to be, meaning whether events flagged as high risk actually correlated with real incidents, and whether events waved through stayed incident free. A system whose escalations do not track with actual outcomes trains operators toward the same complacency that unmonitored equipment produces.
None of this argues against automation in Indian cement manufacturing, where a labor structure built on contract work and a track record of serious accidents make better monitoring an urgent need. It argues for treating human oversight as a design problem with three distinct settings, rather than a single
dial turned up whenever a plant wants to look safer on paper.

About the author:
Dijam Panigrahi, Co-founder and COO, GridRaster, is a spatial computing platform for industrial enterprises and manufacturers.