Al Swaidan has been subcontracted by Consolidated Contractors Group S.A.L (CCC) to crush and screen limestone to be used in the upgrade of 15 km of highway near Doha Qatar. Al Swaidan will produce in excess of 1 million tonnes of 0-75 mm general and selected fill, 360,000 tonnes of Sub Base Class ‘B’ (0-50 mm grading with Liquid Limit 25 and Plastic index 6), and 74,000 tonnes of aggregates for utility bedding.
CCC excavates the material and delivers it to the processing plant, for crushing and screening. The fill and sub-base products need further treatment with the addition of sand to reduce plasticity and the mixing of water to ensure adequate compaction of the product. Once processed Al Swaidan stockpiles each product for the customer to use throughout the project.
Each product has a different price and the customer consumes them at different rates, so Al Swaidan needs to calculate production and consumption by product for billing. They have used surveyors to physically measure the stockpiles, which almost always results in underestimating tonnage. Alternatively they can transfer the material over a truck scale before stockpiling, yet this is a costly process. Al Swaidan needs an affordable way to accurately measure the tonnes produced each month so that they can be paid accordingly.
LOADRITE installed the L2180 onboard scale on the four wheel loaders that were loading or stockpiling the products at the processing area. The LOADRITE Material Management System (MMS) was used to gather the load data from these wheel loaders to provide reports of the tonnage produced. CCC are now billed accurately each month based on these reports.
Affordable and accurate measure of production
Surveying of stockpiles is inaccurate, often underestimating tonnage as the materials own weight compacts it so that it is considerably more dense at the bottom than at the top. Alternatively, transferring materials over a truck scale was accurate yet it required trucks to make a round trip to the weigh bridge that takes at least 12 minutes. This unnecessary trip adds up to over USD 400 in extra costs per day.
Unfamiliar with the LOADRITE system and the degree of accuracy it achieves Al Swaidan conducted a trial between the three options to find the most accurate, fair, and cost effective method. A total of 59 trucks were loaded with a wheel loader equipped with a LOADRITE L2180 scale and printer. The trucks travelled over a truck scale before dumping the material to create a new stockpile. The total weighs for each method were as follows:
- Truck scale: 1,304.38 tonnes
- LOADRITE system: 1,311.42 tonnes (0.54% variation)
- CCC visual survey team: 1,052.87 tonnes (19.28% variation)
- At the average billing rate of $3 per tonne, billing based on each method is as follows:
- LOADRITE system: 1,311.42 t x $3 = USD 3,934.26
- CCC visual survey team: 1,052.87 t x $3 = USD 3,158.61
- Difference; $3,934.26 - $3,158.61 = USD 775.65
Billing based on the survey team’s estimates meant that Al Swaidan would have been under paid by USD 775.65. The LOADRITE system was accepted as the fairest and most accurate method of measurement for both the contractor and the sub-contractor.
Easily track stock movements
The L2180 can be loaded with up to 100 product codes. This makes keeping track of a variety of different products easy. Al Swaidan uses three codes for each of their products:
- Screen to Stock: Product transferred from the crusher to the stockpile
- Screen to Load: Product loaded from the screen product belts for direct delivery to the job site
- Stock to Load: Product that is loaded from stockpiles for delivery to the job site or loaded into the mixing plant
By using product codes Al Swaidan is able to easily keep track of the total quantity of each product produced, stocked and dispatched.
A new level of accuracy
In Al Swaidan’s application they have found some impressive results with the LOADRITE system. The product Sub Base ‘B’ is stockpiled using the Screen to Stock code and then loaded into the mixing plant using the Stock to Load code. In theory, when there is no more stock to load into the mixing plant the total loaded should equal the material stockpiled from the crusher (i.e. Screen to Stock should equal Stock to Load).
Between February and July 2012, in temperatures ranging from 11 °C to 50 °C (51.8 °F to 122 °F), a total of 159,298 tonnes of unmixed Sub Base ‘B’ was stockpiled (Screen to Stock) by various wheel loaders equipped with L2180 scales. Between March and August 2012 the material was loaded into the mixing plant (Stock to Load) until the stockpile was exhausted. The total amount loaded into the mixing plant was 159,236 tonnes, a mere difference of only 62 tonnes.
This 0.04% variation is a good example of the accuracy of the LOADRITE L2180 scales, well within the customer specified +/-1%.
LOADRITE L2180 wheel loader scales and Material Management System
The LOADRITE L2180 wheel loader scales and Material Management System provide an affordable and accurate means to measure production and track stock movements.
Whether you require basic weighing information for a small loader, or greater accuracy and data capture capabilities for production-sized loaders, we have the solution for you.
For more information or advice how a LOADRITE scale can improve your productivity, contact your local LOADRITE representative.