Mobile vs. Static Crushers: The Better Deal

Much in sync with global trend, there is an increased acceptance of mobile crushers in India. This is owing to the advantage offered by the equipment in terms of its mobility, and compactness coupled with host of other benefits. Nonetheless, static crushers continue to enjoy their unparalleled positioning as they are best equipped for high capacity mining activities.Partha Pratim Basistha delves.

There is an increasing preference towards opting for mobile crushers and screeners by quarry operators in India, much in semblance with their global counterparts. The demand choice for a mobile plant is being essentially led by rapidly rising cost of quarry operation, led by lack of qualified manpower to operate the plants. However, change in market demand dynamics brought, owing to the preference of the main project developers or mine owners to remain focused on his core business while outsourcing the quarry operation to contractors owing crushing units has been leading to the market development of mobile crushers in an increasing order.

Development of the market for mobile crushers led by newer demand transition is equally in response due to the multiple benefits offered by the mobile crushing units. The fact contractors owning mobile units are increasingly coming to terms, thereby leading to its enhanced demand.

"Today as per the market trend, 65-70% of the crushing aggregate market is dominated by mobile plants consisting both of wheel and track mounted plants, within which the ratio is greatly in favor of track mounted units. The demand for track mounted plants is being led with the emergence of the segment subcontractors, who have taken over the nitty-gritty of producing aggregates and running quarries in a big way. These subcontractors prefer compact equipment which they can move from site to site at a rapid pace with minimal logistical hassles, given the large volumes of jobs at hand in today’s parlance. In such working circumstance they are finding tracked crushers the right fit,” says Mr. Jaideep Shekhar, Country Manager Terex Finlay.

Further, according to Mr. Shekhar, "being mobile, compact and self-driven, enables the tracked units to operate close to the quarry site, thereby curtailing the use of large conveyors belts, in turn offsetting recurring operating maintenance costs. The other advantage of the tracked equipment are, they can be commissioned and dismantled in a day or a weeks time at the outmost, thereby keeping residual losses at bare minimal, as compared to a static plant.”

Based on its mobile characteristics, the utility mobile crushers can offer in terms of its direct deployment to the quarry site , is also approved by Mr. V. Balasubramanium, General Manager Marketing, Gujarat Apollo. He says, "based on its self propelled and compact value, the track mounted crushers can directly be stationed at the quarry or the aggregate site, thereby offsetting additional logistics costs in terms of conveyor belt or larger number of dump trucks support to the unit to haul the aggregates.” He adds, “cutting down on re–handling through additional support goes on to curtail lead time costs in terms of its output, post starting the machine."

Road construction equipment manufacturer, Gujarat Apollo has recently launched mobile track mounted crushers of 375tph capacity. The crushers are manufactured through technical collaboration with Boehringer of Germany.

Benefits of operating a tracked crusher due to the prime mobility and compactness advantage, which is the integrated feature of mobile crushers is also endorsed by Mr. Rajen Khoda, Director Sales, South Asia & Middle East, Terex Pegson and Power Screen. He mentions, "The value provided by tracked plants owing to their mobile features makes the machines consume less lead time. Owing to its mobile features, the plants can work at pit heads, on contrary to a stationary plant which has to be logistically supported through conveyor belts, and other transportation infrastructure notwithstanding, larger set up time supported by foundations, requiring bigger space area-all taking a higher lead time on operation and output." He adds, "being compact and mobile enables the owner of tracked crushers derive cent percent of its salvage value. Post decommissioning of the plant." According to Mr. Khoda, tracked plants have been registering a growth of 30-35% CAGR growth from the year 2005 onwards.

Besides providing larger residual and salvage value, as compared to static plants the mobile plant has its advantage in terms of flexibility both in terms of installation and operation. As per Mr. Dinesh Sharda, Marketing and Communications Manager, Metso Minerals, "fixed plants offer higher flexibility during design stages but become quite inflexible on installations. The residual loss of fixed plants are high leaving behind civil works and wastage in plant structurals and electricals. As a reason, it makes sense to build a fixed plant if the plant has to stay in place for many years, otherwise mobile plants make a better sense."

Similar views are echoed by Mr. R.S, Raghavan, Managing Director, Proman. According to him, "both wheel and tracked mounted plants are relocatable. This makes them easier to install than fixed static plants. Static plants have the advantage in that they can be installed to provide higher aggregate output although it takes more time to install the same." However, he mentions, "mobile crushers are preferred for projects wherein it is easy to complete the project to move on to the next project. If the customer is sure of working in an area for over five years in case of a typical commercial producer), it is always to go for fixed static plants.

The mobility factor advantage is also subscribed by Mr. Abhijeet Pai, Director, Puzzolana Machinery Fabricators. According to Mr. Pai "the prime feature of mobility advantage makes both the track and wheel mounted crushers ideal to deploy at sites to have lower gestation period as they can both be commissioned and deployed at a shorter duration as compared to static crushers. Besides, the machines have less salvage value." However, Mr. Pai concedes mobile crushers are ideal for sites providing output requirement at 200-300 TPH. Puzzolana manufactures trolley mounted crushers are leaders in this segment with the highest market share in trolly mounted crushers.

Evaluating Mobility Advantage

Flexibility of the machines is based on its mobile and self–propelled features, which according to manufacturers allows the mobile plants deliver cost efficiency. The aspect of cost efficiency involved in mobile crushing and screening units can be better explained highlighting the conditions in which mobile plants usually work. As per this, being smaller compared to fixed plants mobile plants are operated in smaller quarries to match lower production volumes. Being smaller in size mobile units can easily be moved between sites. As a result, the company that operates a number of quarries in a particular area may be able to do so by investing in just one set of crushing and screening equipment, plus trucks and trailers.

Added to the mobility element there are also multiple benefits provided by mobile crushers as compared to static ones. According to Mr. Swapan Das, Director, Extec Screens & Crushers (India) Private Limited," the benefits are numerous, which makes them have an edge over a static unit. This is based on the fact that owing to its compressed features the machines have bare minimal gestation period, post commissioning. The other benefits come in the form of easy adaptability to plant capacities and configuration to accommodate changing feed character and product demand." Mr. Das points further, "above all owing to its ambulatory features the units can be stationed and used for multi–quarry and multi-project applications. Besides the machines are easy to operate and maintain."

As per Mr. Das the assorted benefit of the mobile units has led their population grows in the Indian market. Growth in volumes has been led both through additions of newer customers and the existing ones expanding their fleet. According to Extec, year 2008 saw a 50% growth over 2007 with sale of over 350 units. Mr. Das points out "plant size of a mobile unit will depend on the feed sizes/material character/desired product sizes and distribution, the most common plants in aggregates are around 200 TPH and in Mining around 250-300 TPH. However, a modern Mobile plant today covers almost the entire range of crushing and screening applications upto 400 Tonnes per hour."

Going by the benefits, the use of mobile crushers also allows a change from traditional quarry working methods. According to Mr. Shankarnarayan, Vice-President Operations, Taurian Engineering "rather than hauling blasted rock from the face to a fixed crushing and screening plant-a long journey in many quarries-the use of mobile units means the primary crushing stage can be carried out next to the phase itself. Tracked machines can be moved in close when it is time to crush and shifted out of the way during blasting."

The other advantage of primary crushing, owing to its mobile features is at the face is that it cuts out the process of hauling large rocks over long distances. Once crushed, materials is easier to handle and transport and may even open the door for conveying systems to move the material from the face to fixed secondary and tertiary crushers and screens. However, this may not reduce the total distance that material has to travel from the face to the final stockpile, but it can help reduce the transportation of bulky material. The cost efficiency advantage here is that such a system could reduce the need for large haulers and loaders, which cost a lot to run in term of fuel and other consumables such as tyres.

Apart from providing complete solution for pure mining and quarrying applications, mobile plants are used in other areas of industry. This can be often found in construction projects that are taking place in rocky terrain–particularly road building schemes. Once rock is excavated often by blasting the mobile crusher is used to reduce it to a size where it can either be trucked away or disposed of off site, or reused as aggregate on the project. Builders of NHAI road building project in the country have been using portable and mobile plants. The builders have learnt by experience that portable or mobile plants would provide them a more crushing period in short schedule compared to fixed plants. Suiting to the requirements of construction and mining industry mobile crushers have been finding their way into the demolition and recycling industry as well.

In tandem providing with cost efficiency, mobile crushers are also ideally suited to match environmental safety parameters as well. This also makes it rightly able to be used in Indian conditions, as there is a growing concern for environmental safety. As mobile crushers operate in smaller quarries, it has less impact on environment. As because by definition, smaller quarries have less impact on environment. There is the obvious point that less extraction means less direct impact, but there are also knock-on-effects. For example, a lower production volumes at site means there will be fewer truck journeys to and from it.

Benefits of Static Plants

But nevertheless, despite multiple benefits provided by mobile plants, fixed crushing and screening plants always possesses an edge in the market at large for its ability to operate in high output quarries that are operated over several decades. According to Mr. V. Venkataramana, Vice-President-Construction Segment India Sandvik Mining & Construction, "deployment of static plant has much to be need based justifying higher aggregate output requirement." He mentions, "if a plant has a throughput in excess of 500 tones per hour–about one million tones per year based on eight-hour days and five days week large fixed crushers and screens will be the best option. While mobile plants would be ideal to meet aggregate throughput between 250 tph-500 tph." This is agreed by Mr. G.N. Raju, Managing Director, NAWA Engineers and Consultants Pvt. Ltd, manufacture of mobile and static crushers.

According to him "the mobiles are not always ideal machines for all situation, for example, dam projects. The dam projects generally have longer construction schedules. The mobility feature at a higher initial investment may not pay back. Most of the dam projects go for fixed plants, as time schedules can accommodate longer plant set up times." He mentions further, "a well built fixed plant offers more flexible production of different grades of aggregates, as they are built to specific flow designs matching to the users crushing tasks. Fixed crushers are adaptable to tuning up with little changes to produce from coarse to fine aggregates to crushed sand."

Used for yielding, larger aggregates volumes at a range of 700 tph–1000 tph or above and for large scale construction projects make fixed plants larger in size and ideal for application. As a result, heavy RCC foundations are required to set up the plant and the plants are custom designed to suit the given crushing task. The enormity of the plants requires substantial time to set it up. For instance, a 700 tph plant would take a total of 12-16 weeks to set up from zero date. This besides, the plants are provided with surge piles/surge bins to regulate the feed to secondary and tertiary crushers which increases the crushing performance.

Being ideal for long duration crushing at a single point and to produce varied products, fixed plants can be more closely controlled to get better quality products. Further, the plant can be operated at optimum efficiency that gives a better output. But being larger in size the dismantling and movement of fixed crushers involves enhanced time and costs.

However, though despite possessing certain restrictive parameters towards mobility, fixed plants will always continue to have a place in the aggregate production industry, but again observing the larger trend on a macro level it can be derived that there is an increasing role of mobile equipment. But as per the objective assertion of the industry leaders that 500 tph is the upper limit of the mobile crushers puts restrictive parameter on the optimum usage of mobile units. This broadly indicates both the units have their advantages and deficits. Hence, before choosing the right system, it would require an open mind and a careful, case by case assessment of each situation by the users prior selection of the crusher.

Selecting the Right Plant

Assessment of situation, prior to purchasing the right kind of plant has to be broadly carried out through an analysis of working economics of plants. Without analyzing of working economics, it would be difficult to draw a line on economics between a mobile and fixed plant based on plant capacity. Depending on the analysis made, the user has to understand the concerned plants application, which would decide the kind of plant that would give him a better utility.

Evaluating the features offered by the static and mobile plants, the concerned has to set up the right capacity plant with right configuration, which will fulfill his crushing task. Matters like project period, the total crushing quantity, the available crushing period, the set up time, the crushed stone sizes, the characteristics of stones to be crushed, the loss of time due to monsoon would be some of the important factors for an assessment, that needs to be considered for arriving at the optimum capacity of the plants. For optimum utilization of the plants further better economies of scale has to be formulated.

This is essential as the users may face problems in their efforts to put up a static plant for obtaining optimum level of operation and out. As Mr. Raju emphasizes, this has been put the main bottleneck towards effective utilization of plants by the users in India. He explains, "to have better economies of scale the users should focus on establishing a continuous and reliable supply chain between the plant and the quarry that would deliver the right size of boulders and tons per hour." All these would enable the user to maximize the utilization of the plants thus allowing them to attain a better breakeven.