GENERAL INFORMATION AND THE NEED OF CHECKING THE WEIGHT OF STOCKPILE BY 3D LASER THEODOLITE

Companies or industries maintaining large inventory in bulk, for business planning, financial report, loan, inventory forecast, regulatory requirement, performance measurement and other reasons, it is often necessary to determine the quantity in the inventory. However, the vast amount of inventory in stockpiles makes the weighing impractical and cost prohibitive. These difficulties have been overcome by Stockpile Survey. Stockpile Survey is a technique to measure the volume and weight of commodity stockpiles. It is a scientific/instrumental method, using the equipment called Total Station (3D LASER THEODILITE) to determine the volume of the stockpile quantity. This method has been widely used in countries in this region like Malaysia, India, Thailand, China, Indonesia and Australia.

EODR (Laser) Calibration System for stockpile survey

-       Laser Motorized  Reflectorless Theodolite of extended range

-       Calibration Charts software

TPS Leica 1200⁺ serials

Main Characteristics of Laser

-       Reflectorless range - 2000 metres

-       Prism Range – 10,000 metres

-       Distance accuracy 2 mm + 2mm/km

-       Laser dot size 2cm/50m

-       Angle accuracy - 0.0003 degree

-       Speed of readings up to 30 per minute

-       Memory capacity - 64 Mb

-       Electronic Level compensator

International Recognition/Legal base

-       Calibration is done to the ISO7507 (BS7723) Part 4 (Internal) and Part 5 (External) methods of calibration

-       Method is recognised by NATA

-       Equipment is battery powered - safe for hazardous areas. However hot work permit is required.

PROCEDURE FOR CARRYING OUT STOCKPILE SURVEY

Any shape of stockpiles can be measured as long as the whole surface must be visible. The measurements (data from site) are automatically stored in the data logger (data collector) of the Total Station instrument. The collected data is digital signal which indicated:

-       The distance from zero point in the machine to the checked point.

-       The horizontal angle and vertical angle.

-       The altitude of checked point to standard horizontal plane.

These data will be downloaded to PC to calculate the volume and generating contour map by using Civil cad software. Bulk density is determined by actual field test average results of individual stockpile. The weight of the inventory is derived by volume multiply the tested density of the commodity.  

Summary of procedures and limitations of stockpile survey findings as follow:

a)    Measurement of material piles bulk densities at site. All bulk densities to be determined by weighing of some random samples of cargo from each stockpile on site using portable standard size container and weighing scale or using truck. The test will be limited to top layer of stockpile cargo only after having the test materials moved or loosen thus affecting its compactness. The varying degree of compactness (possible varying or higher density) of the inner and lower level material of the stockpile will not be taken into our calculations.

b)    Calculate volume of each stockpile by Topographic Survey using Total Station and computation by Civil cad software

c)    Quantity volume of pile obtained by multiplying the volumes calculated and the tested bulk densities. Quantities established are for reference purposes only.

d)    All identification of cargo piles & their boundaries to be declared by client prior to commencement of survey.

e)    Description of all commodities is as per declaration by client and not as a certificate of grade or commodity by ITVC.

f)     f)  There should not be any movement for the particular piles while being surveyed. Movement of a particular pile can be resumed after ITVC have    completed measurement.

g)    All base layers are assumed flat.

h)    All identification of cargo piles & their boundaries to be declared by the Client prior to commencement of survey.

i)      Survey at yard not carried out during raining.

j)      The quantities reported are at the date & time stated in the survey report only and does not refer to any other matters.

Typical shape of cargo in stockpile 

ACCURACY OF DETERMINATION OF STOCKPILE SURVEY BY LASER METHOD

Taking into consideration of some of the above limitations, based on our experiences and feedbacks from clients, the accuracy for homogeneous cargo sizes can be +/-1% and non-homogeneous cargo sizes can be +/-3%.

CHARECTORESTIC OF STOCKPILE SURVEY BY LASER METHOD

-       The data was obtained at site by TPS (3D laser theodolite) will auto-saved with high accurate in distance, angle and altitude of position of checked point so that have no human error on recording and transferring data.

-       The calculated volume is issued by processing in professional software with the most accurate.

-       The tested weight will be done on the composite sample which used the high-technique sampling (Used the Vacuum deep sampler).

-       This method will be applied for checking weight of various kind of cargo in stockpile (steel scrap, pig iron, iron ores, clinker, cement in bulk, sand, gypsum, lump stone, agriculture products, woodchips, coal…)

-       For this technical, we can determine the weight of cargo in stockpile with any shapes.

-       No need to re-weighed, Fast & Safe and mobility of equipments so we can do the checked weight of a large quantity of cargo in a short time thus we will save the time and cost.

To request for the Stockpile survey services - Please contact ITVC Global - you'll get useful advice and the best service.