MXPA99001713A - Real time optimization for demezcl beds - Google Patents

Abstract

During the construction of a mixing bed of variable bulk materials from which sections of bulk materials are periodically retrieved, a computer (30) processes the composition analyzes (54) and the quantitative measurements (S6) to provide a basis for Real-time data (74) of the current aggregate composition of the bulk materials in respective sectors of the mixing bed and further process the current compositional analyzes and the current quantitative measurements with the real-time database to predict a composition of aggregate (AP) of materials to bulk the respective sectors of the mixing bed when the respective sectors are recovered. When the predictions of the aggregate composition indicate that stacking a given bulk material at a given point of the mixing bed would cause a given sector of the mixing bed to have an undesired aggregate composition when the given sector of the mixed bed is recovered. When mixed, the computer causes the stacking of the bulk material to be omitted as it is being delivered to the given location of the mixing bed and further causes that at least one correcting bulk material is stacked at the given point by the mixing bed subsequent to the omission in order to cause the given sector of the mixing bed to have a desired aggregate composition when the given sector of the mixing bed is recovered

Description

REAL TIME OPTIMIZATION FOR MIXING BEDS DESCRIPTION OF THE INVENTION The present invention generally relates to mixing beds for construction with different bulk materials, from which parts of bulk material are removed periodically, and is directed particularly to improved systems. and computer readable storage media for determining the compositions of the mixing beds as they are being formed and for stacking the bulk materials in the mixing bed in such a way as to form a mixing bed having a desired composition in the mixing bed. all 'he mixed bed. Variable bulk materials include different types of bulk materials and / or bulk materials of a given type having varying compositions. Mixing beds, also known as combination beds, are widely used in the cement industry and other industries, such as coal, mining, grain and fertilizer processing, to reduce the variability in bulk materials when They process, as if to provide storage in heaps to process "when material production or material transport systems are stopped." Although mixing beds are sometimes used to homogenize the material obtained from a single source, the beds Mixing materials are often used to homogenize different materials sent from different sources, such as mixtures of lime and clay for use in cement plants and coal mixtures with high and low sulfur contents for use in power plants. present invention to reduce the variability in the mixing bed in such a way that it will not be required to later homogenization. The mixing beds are composed of many layers of bulk material. Figure i shows a typical longitudinal mixing bed 10 in which a stacker 12 moves forward and backward along the spine 14 of the mixing bed 10 and stacks several layers of variable bulk materials. The bulk material is taken to the stacker 12 from a selected source of bulk materials by means of a conveyor 15. Figure 2 is a cross-sectional view of the mixing bed 10 taken normal to the movement of the stacker 12. The material in bulk isolated on the spine 14 of the mixing bed 10"by means of the stacker falls on the face of the mixing bed 10 to be distributed in lamellae, as shown in Figure 2, where the respective layers L become thinner as the height of the mixing bed 10 increases, as also shown in figure 2. While a mixing bed 10 is constructed, parts of the bulk material are recovered by means of a recuperator 16 from a previously mixed bed constructed 10 ', the recuperator 16 removes the bulk material from the mixing bed 10' while advancing from one end of the mixing bed 10 'to the other. bulk of a mixing bed 10 at an angle with respect to the stacked layers L which is inclined to be equal to or slightly greater than the angle of repose of the bulk material. By means of this process, the material of a large number of layers L is simultaneously recovered from the mixing bed 10 'and combined to be an aggregate composition that combines the respective compositions of the mixed layers L. Typically, the respective compositions of the layers are 'select to produce the desired aggregate composition of the whole mixing bed 10. Since the layers are independent of each other, the variations are mainly random, and the recovery process recovers a portion of a large number of L layers simultaneously with a homogenization effect that is approximately proportional to the square root of the number of L layers intersected by the recuperator. Figure 3 shows a circular mixing bed of continuous mode 20, which is constructed by rotating the stacker 22 by continuously stacking the bulk material on the spine 23 which thus extends continuously towards a mixing end which extends continuously 24 at one end of the mixing bed 210 while the bulk material is continuously recovered from the other end 20 of the mixing bed 20 upon rotating the recuperator 26; thus there is no need to move the stacker 22 and the recuperator 26 from one mixing bed 20 to another. Both the stacker 22 and the reclaimer 26 rotate in the same circular direction 27 about a common central axis 28. The bulk material is sent to the stacker 22 from a selected source of bulk material by means of a conveyor 29. Bulk material stacked on the spine 23 by means of a stacker 22 collapses the faces of the mixing bed 20 distributed in layers, as shown in Figure 2. The stacker 22 moves back and forth in the circular direction 27 a along the spine 23, typically with a fixed height above the spine line, to produce overlapping layers as shown in Figure 4, which is a vertical sectional view of the mixing bed 20 taken in alignment with the circular direction of the movement 27 of the stacker 22. The respective layers L are shown with an arbitrary constant size but can be physically distinguished from each other only when there are variations in the bulk material which e is being deposited on the spine 23. In the prior art, the length of the mixing tail 24 is determined by the requirements for homogenization of the bulk material. As shown in FIG. 4, the layers L of the circular mixing bed 20 are stacked in an inclined manner, the angle of inclination being selected in such a way that the desired glue length is equal to or less than the rest angle. of the bulk material. These layers L have a length determined by the angle of inclination and the final height of the spine 23. The recuperator 216 recovers the bulk material from the mixing bed 20 in the same way that the recuperator 16 recovers the bulk material from the mixing bed 10 ', as described above with reference to figure i. In order to build a mixing bed having an aggregate composition desired predetermined amounts of selected bulk materials are brought to the mixing bed to be stacked by the stacker according to a plan such that the respective sections of material to Bulks which are recovered from the mixing bed according to the homogenization capacity of the mixing bed have a desired aggregate composition within an acceptable range of aggregated compositions. Sometimes, however due to equipment failures or other problems, those variations in the composition of a particular selected bulk material, one or more of the selected bulk materials are not immediately available, making it impossible to build the Mixed bed according to a plan. Since the process of forming the mixing bed is not interrupted when this condition occurs, it is possible that several sectors S of the mixing bed have an undesirable aggregate composition. The sector is a three-dimensional lateral segment of an arbitrary size and extends between the upper and lower part and towards the sides of the mixing bed 10, 20 in an orientation that is vertical as shown in Figure 4, and approximately normal to the direction of advance of the recuperator 16,26. In a circular mixing bed 20, a sector S can also be delineated by radii and a portion of the circumference of the mixing bed. Various on-line analysis and / or sampling techniques are used to determine the aggregate composition of a mixing bed as the mixing bed is constructed in such a way that an undesired aggregate composition of a given sector S of the mixing bed can be recognized. and then it can be corrected. For example, a bulk material analyzer, such as an analyst using point-range gamma-ray neutron activation (OGNAA) analysis, is placed around a conveyor that carries bulk material to the stacker to analyze the composition of the bulk material that is being sent to the stacker; and the amount of bulk material of such composition that is being delivered to the stacker is gravimetrically measured by means such as scales placed within the conveyor assembly. A disadvantage that occurs in the formation of continuous circular mixing beds 20 compared to the formation of longitudinal mixing beds 10 does not have the ability to correct an undesirable aggregate composition of an individual sector S located between the upper part of the tail of mixed 24 and the other end 25 of the circular mixing bed 20 without having to interrupt the formation of the mixing bed 20. The mixing beds 10 are considered to have a coherent aggregate composition, between, but not in, the end portions due Because they are formed by hundreds of thin horizontal layers that cover the entire length of the mixing bed, an undesirable aggregate composition of a longitudinal mixing bed 10 can be adjusted at any time by simply adding additional layers of a corrective bulk material; while the bulk material is added to a continuous circular mixing bed 20 alone in the mixing tail 24 such that there are sectors S with an undesirable aggregate composition located between the top of the mixing tail 24 and the other end 25 of a continuous mixing bed 20 where the bulk material is being recovered, can no longer be corrected during the continuous form of operation and can be corrected only by adding correction material to those sectors after the continuous formation of the mixing bed It has been interrupted. For this reason many operators of circular mixing beds have selected to operate them in batches which allows the correction in the same way as in the longitudinal mixing bed, where bulk corrective material is added uniformly on the lot that caused "the bed of mixing has an undesirable aggregate composition.A previous technique for correcting irregularities of the aggregate composition detected in a bed of continuous circular mixing while forming the mixed faith bed, as described by Ahrens, "Latest Developments in Circular Mix Bed Technology "Bulk Solids Handling, vol.17, 'No. 2, April / June 1997, pp. 257-263, is to take samples and analyze the composition of different layers of the circular mixing bed as it is formed and stacking an upper layer of bulk correction material when it has been determined by that analysis that the layers of bulk material that are being superimposed do not have the default aggregate composition. However, this technique does not seem to be applicable to correct irregularities of the aggregate composition detected in given sectors S of the mixing bed 20 while forming the mixing bed 20.

The present invention provides improved systems and methods for being used to correct irregularities in the aggregate composition detected in given sectors of the mixing bed while the mixing bed is being formed. In one aspect the present invention provides a system for forming or building a mixing bed of variable bulk materials, from which sections of bulk materials are periodically recovered, consisting of means for constructing a mixing bed composed of many layers of variable bulk materials when stacking variable bulk materials received in the mixed bed at different points according to a plan; means for analyzing the composition of the bulk materials being received for stacking in the mixing bed: means for measuring the quantities received of bulk materials to be stacked in the mixing bed; means for correlating composition analyzes and quantity measurements with the different places to which the bulk materials are taken to stack them; and means adapted to process the composition analyzes and the quantitative measurements with the position correlations to predict, according to the compositions and quantities of the bulk materials being carried to stack them in the mixing bed, an aggregate composition of bulk materials in respective sectors of the mixing bed when the respective sectors are recovered. Such a system may comprise means adapted to respond to the predictions by causing the stacking of a given bulk material at a given place in the mixing bed to be omitted, when it is predicted that the stacking of the given bulk material brought to a given point of the The mixing bed would cause a given sector of the mixing bed including the given bulk material brought to the given point to have an undesired aggregate composition when the given sector of the mixing bed is recovered. That system may also comprise means adapted to respond to that prediction of undesired aggregate composition by causing at least one bulk correction material to be stacked at the given place in the mixing bed after the omission in order to cause that sector of the The mixing bed has a desired aggregate composition when the given sector of the mixing bed is recovered. Accordingly, irregularities in the aggregate composition in one or more of the given sectors of the mixing bed can be selectively corrected without interrupting the continuous formation of the mixing bed. In another aspect the present invention provides a system for constructing a mixing bed of variable bulk materials, from which sections of the bulk materials are periodically recovered, consisting of means for constructing a mixing bed composed of many layers of materials a bulk variables when stacking the various bulk materials delivered in the mixing bed at different points according to a plan, - means to analyze the composition of the bulk materials that are being received for stacking in the mixing bed: means for measuring the quantities received of bulk materials to be pilfered in the mixing bed; means for correlating composition analyzes and quantity measurements with the different places to which the bulk materials are taken to stack them; and means adapted to process the composition analyzes and the quantitative measurements with the position correlations, to provide a real-time database of the current composition of the bulk materials in respective sectors of the mixing bed. These systems may also consist of means adapted to process the composition analyzes and the quantitative measurements with the position correlations to predict, according to the compositions and quantities of the bulk materials that are being carried to stack them in the mixing bed., an aggregate composition of the bulk materials in respective sectors of the mixing bed when the respective sectors are recovered. The present invention also provides methods for constructing a mixing bed of variable bulk materials, from which sections of the bulk materials are periodically recovered, the methods corresponding respectively to the operation of the above-described systems provided by the present invention. In still another aspect, the present invention provides a system for constructing a mixing bed of variable bulk materials, from which sections of bulk materials are periodically recovered, consisting of a stacker for feeding the bulk materials and for depositing the bulk materials. bulk materials in a plurality of different spots of the mixing bed to sequentially construct a plurality of stacked layers of bulk material throughout the mixing bed; a stacker locator for providing a position signal indicating the location in which the stacker is depositing the bulk material; a composition analyzer for determining a composition of the bulk materials that are being deposited by the stacker and for providing a composition signal indicating the determined composition; a quantity measurement system for measuring a quantity of the bulk materials being fed by the piler and for providing a quantization signal indicating the measured quantity; and a computer coupled to the locator of the stacker, the composition analyzer and the quantity measurement system to receive the position signal, the composition signal and the quantity signal, where the computer is adapted to process the position signal , the composition signal and the quantity signal to correlate the position in which the stacker deposits the bulk material with the composition and quantity of the bulk material that is being deposited in that location and to calculate an aggregate composition that is predicted bulk materials within a selected sector of the mixing bed formed by the deposit of the bulk material in that position. The present invention also provides a system for use in a method for constructing a mixing bed composed of many layers of variable bulk materials, from which sections of the bulk material are periodically recovered, the method includes the steps of constructing a mixed bed. composed of many layers of variable bulk materials when stacking the variable bulk materials received in the mixing bed at different points according to a plan; analyze the composition of the bulk materials that are being received to be stacked in the mixing bed: measure the quantities received of bulk materials that are going to be stacked in the mixing bed; and correlating the compositional analyzes and the quantity measurements with the different places to which the bulk materials are taken to stack them; the system comprises means adapted to process the compositional analyzes and the quantitative measurements with the position correlations to predict, according to the compositions and quantities of the bulk materials being carried to be stacked in the mixing bed, a composition of aggregate of the bulk materials in respective sectors of the mixing bed when the respective sectors are recovered and means adapted to respond to the predictions by causing the stacking of a given bulk material at a given place in the mixing bed to be omitted, when it is predicted that the stacking of the given bulk material brought to a given point of the mixing bed would cause a given sector of the mixing bed including the given bulk material taken to the given point to have an undesired aggregate composition when the given sector of the Mixed bed is recovered. The present invention also provides a computer readable storage medium for use in a computer used in a method for constructing a mixing bed composed of many layers of variable bulk materials when stacking the variable bulk materials received in the Mixing Ceil in different points according to a plan; analyze the composition of the bulk materials that are being received to be stacked in the mixing bed: measure the quantities received of bulk materials that are going to be stacked in the mixing bed, and correlate the composition analyzes and the measurements of quantity with the different places to which bulk materials are carried to stack them, where the storage medium is configured to cause the computer to process compositional analyzes and quantitative measurements with position correlations to predict, according to the compositions and quantities of the bulk materials being carried to stack them in the mi bed, -an aggregate composition of the bulk materials in respective sectors of the mi bed when the respective sectors are recovered. In another aspect the present invention provides a computer readable storage medium for use in a computer used in a method for constructing a mi bed composed of many layers of variable bulk materials when stacking the variable bulk materials received in the bed of mixed in different points according to a plan; analyze the composition of the bulk materials that are being received to be stacked in the mixing bed: measure the quantities received of bulk materials that are going to be stacked in the mixing bed; Y. correlate composition analyzes and quantity measurements with the different locations to which the bulk materials are carried for stacking, where the storage medium is configured to cause the computer to process compositional analyzes and quantitative measurements with the position correlations to provide a real-time database of the current composition of the bulk materials in the respective sectors of the mixing bed. Additional features of the present invention are described with reference to the detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates the construction of a longitudinal mixing bed according to the prior art and the recovery of bulk material. Figure 2 is a vertical sectional view of a prior art mixing bed, such as the longitudinal mixing bed shown in Figure i or a circular mixing bed, taken normal to the movement of the stacker. Figure 3 illustrates the continuous formation of a circular mixing bed of the prior art and the recovery of 1 bulk material thereof. Figure 4 is a vertical sectional view of a circular mixing bed of the prior art, as shown in Figure 3, taken in alignment with the circular direction of the movement of the stacker. "Figure 5 is a block diagram of the systems and methods of the present invention, Figure 6 is a vertical sectional view of the mixing bed taken in alignment with the direction of movement of the stacker, with sectors inclined at an angle. which corresponds to the angle at which the sections are recovered from the mixing bed Figure 7A illustrates a predetermined model of the construction of a non-circular mixing bed, with which the systems and methods of the present invention are particularly useful.

Figure 7B is a vertical sectional view of the mixing bed of Figure 7A, taken normal to the movement of the recuperator. Figure 8A illustrates another predetermined model of the construction of a mixing bed with which the systems and methods of the present invention are particularly useful.

Figure 8B is a vertical sectional view of the mixing bed of Figure 8A, taken normal to the movement of the recuperator. Figure 9 shows an algorithm for calculating a prescription for the composition of a subsequent layer of the mixing bed. Figure 10 illustrates the use of the present invention.

Referring to Figure 5, a preferred embodiment of the system according to the present invention for constructing a mixing bed for variable bulk materials, from which sections of bulk materials are periodically retrieved, includes a data processor or computer 30, a stacker 32, a stacker position monitor 34, a feed rate monitor 36, an on-line bulk real-time material composition analyzer 38, a quantity measurement system 40, such as a conveyor belt scale u another mass flow measuring device, and a bulk material selection system 42. The bulk material selection system 42 selects different bulk materials selected to be sent to the stacker 32 from different sources either in response to a plan of selection of computer generated material 46 or according to a selective operation control. Stackers and stacker / reclaimers are well known in the art and can include a variety of radial stacker or homogenization stores as well as other transport and stacking equipment suitable for use in homogenization and mixing applications. The stacker 32 forms a mixing bed composed of many layers of variable bulk materials by stacking the variable bulk materials conveyed to the mixing bed at different points in accordance with a delivery position plan 44 generated by means of a "routine". delivery plan "48 executed by the computer 30. The" delivery schedule "routine 48 also generates the material selection plan 46 that selects different bulk materials for delivery to the stacker 32 from different sources and provides the plan 46 to the bulk material selection system 4. An operator of the bulk material selection system 42 can override the material selection plan 46 provided by the "delivery plan" routine 48. The operator of the bulk material selection system 42 can make the selection system of bulk material 42 I sent an alternative delivery position plan 44a to the stacker to override the delivery position plan 44 provided by the "delivery schedule" routine 48. The position of the stacker 32 is important for (a) for determine the identity of the sector of the mixed bed that is receiving the material and (b) provide the percentage of completion of the current layer. The position monitor of the stacker 34 continuously monitors the position of the stacker 32 and provides position signals from the stacker 50 to the computer 30, which temporarily stores the position data of the stacker indicated by the signals with respect to time. position of the stacker 50. The position monitor of the stacker 34 uses position sensors at known positions to monitor the position of the stacker. In an alternative embodiment, the position monitor of the stacker 34 records the "direction and speed of movement of the stacker and processes the recorded data relative to a known starting point to compute the monitor location of the stacker. Stacker position monitors are well known in the art and include laser measurement systems, that is, optical base systems, as well as electrical and electro-mechanical measuring systems. A system of positioning position means of the commercial laser-based stacker is the Lasermeter LM4 distributed by Laser Measurement of Midrand, South Africa. The delivery rate monitor 36 continuously monitors the speed at which the bulk material is delivered to the stacker 32 to be stacked in the mixing bed and provides delivery rate signals 52 to the computer 30, which temporarily stores with respect to at the time the delivery speed data indicated by the delivery speed signals 52. Preferably the delivery rate monitor 36 measures the speed of the conveyor which is delivering the bulk material to the place where the bulk material is stacked in the mixing bed. Appropriate delivery rate monitors exist commercially and include optical, electrical, electro-mechanical, ultrasonic, and microwave flow rate instrumentation. The Bulk Material Composition Analyzer 38 continuously analyzes the composition of the bulk materials being delivered to be stacked in the mixing bed and provides real-time composition analysis signals 54 to the computer 30 temporarily storing with respect to at the time the composition analysis data indicated by the composition analysis signals 54. Preferably, the bulk material analyzer 38 performs the PGNA analysis, although other real-time analysis systems may be used. Exemplary PGNAA systems and methods are described in U.S. Pat. No. 4,582,292 of Atwell et al. and 5,396,071 to At ell et al. and in the pending United States patent applications nos. 08 / 492,575 and 08 / 822,075 whose descriptions are incorporated for reference. The quantity measurement system 40 measures the quantities of the bulk materials that are delivered to be stacked in the mixing bed and provides real-time quantity measurement signals 56 to the computer 30, which temporarily stores the measurement data. of quantity with respect to time by means of the quantity measurement signals 56. Preferably, the quantity measurement system 40 includes a scale placed within the conveyor assembly. The data indicating the position of the analyzer of the composition of the bulk material 38 and the data 60 indicating the position of the quantity measuring system 40 are input to the computer 30. The quantity measuring system 40 preferably travels with the end output of the stacker 32 in such a way that the position monitor of the stacker 34 will also provide the data indicating the position of the quantity measuring system 40. If however, the position of the quantity measuring system 40 is independent of the output from the stacker 32 and is not at a fixed point, a separate position monitor (not shown) is provided in order to provide the data 60 indicating the position of the quantity measurement system 40. The computer 30 includes a processor of data and at least one memory to store the control / monitoring software and the analyzer software, as well as the temporary storage for raw and processed data. os.

Interfaces that include the appropriate hardware and / or software (not shown) are provided for data communication and the operator interface. In a preferred embodiment, the computer 30 is a personal computer (PC), such as a PC with a PENTIUM processor that has a 200 HZ CPU card with 64 MB of RAM, a large capacity (2.1 GM) hard drive for storage of large databases, a CD-ROM drive, and a high-resolution graphics monitor and printer. Due to potential dust contamination, the computer 30 must be housed in a housing suitable for the environment, which may include temperature and humidity control devices. The computer 30 determines the composition of the aggregate bulk material? ^ For different respective sectors S of the mixing bed. The given sectors may be vertical as shown in Figure 4, but preferably they are inclined from the vertical with an angle corresponding to the angle at which sections of the bulk material are recovered from the mixing bed as shown in Figure 6. With the In order to account for the respective time delays of the generation times of the analysis signals of the composition 54 and the quantity measurement signals 56 at the time of deposit in the mixing bed of the bulk material to which those signals relate. 56, the computer 30 executes a data processing routine 62 indicated by the position signals of the stacker 50, the delivery rate signals 52, the composition analysis signals 54, and the quantity measurement signals 56.; the data 58 indicating the position of the analyzer of bulk material composition 38; and the data 60 indicating the position of the quantity measuring system 40 cdn in order to correlate the composition analysis data indicated by the composition analysis signals 54 and the quantity measurement data indicated by the quantity measurement signals. 56 with the different positions to which the bulk materials are being carried for stacking and provides position correlation data 64. In an alternative embodiment, the data 50a indicating the planned position of the stacker, which is provided by means of the "delivery schedule" routine 48 is processed during the execution of the correlation routine 62 in place of the data indicated by the position signals of the stacker by the position signals of the stacker 50 provided by the position monitor of the stacker 34. The respective time delays of the generation times of the composition analysis signals 54 and signals The measurement of quantity 56 at the time of deposit in the mixing bed of the bulk material to which the signals refer, is determined from the delivery speed signals 52 and the known travel lengths of the bulk material at the time of deposit. place of deposit from the respective positions in which the composition of the bulk material is analyzed and the amount of the bulk material is measured. The computer 30 executes a routine 66 for processing the correlation data 64 with the composition analysis data indicated by the composition analysis signals 54, and the quantity measurement data indicated by the quantity measurement signals. to determine the amount Mn and the composition C-, in the different sectors S of a new layer Ln of the bulk material that are applied to the mixing bed as a result of the measured quantity M "and the composition analyzed C? of the bulk material that is being stacked in the mixing bed at a given point by the stacker 32 and provides correlated data 68 indicating the amount M "and the composition C" of the new layer Ln being applied to the mixing bed in different sectors S of the mixing bed. C. can be the proportion of each element present, an amount derived from the elementary measurements, or any other measurable and useful quality obtainable from an in-line analyzer of bulk material. The routine 66 compensates for the characteristics of different types and / or sizes of materials within the bulk material stacked at a given position by knocking respectively at different distances from the given distance towards an edge of the mixing bed by adjusting the amount M-, and the composition C of the new layer L in the given sector S according to the characteristics of collapse. The amount of that composition is determined empirically by analyzing the samples at different distances from the given position. The computer 30 executes a routine 70 of adjusting an aggregate material composition aggregated ^ for given sectors S respective stored in the database memory 74 according to the new composition and the quantity data 68 and stores the composition data of "aggregate bulk" material adjusted for all S sectors completed and not terminated in the database memory 74 to provide a real-time database of the current composition of the bulk materials in the given sectors S of the bed The routine 70 determines the composition of aggregate bulk material A "for each given sector S according to the following calculation: A» = (Cl * Ml + C2 * Ma + ... Cn * Mn) / (M1 + M2 + .. Mn) (Equation 1) where n is the number of layers in a sector at the time the calculation is made Separate calculations are made for each measured element or quality, for example A ^ for calcium, A ^ for silicon, Ap3 for iron, etc. Algu These are qualities of the composition such as the lime saturation factor (LSF), which is well known and widely used in the cement industry as a key measure of cement quality. It can not be combined linearly. LSF is a particular ratio of calcium to iron, silicon and aluminum. In those cases in order to obtain the most accurate measurement of the particular quality, the concentrations of each of the elements are combined as in equation 1, each being considered a separate quality, and then the "LSF is calculated for the aggregate sector or the portion of 1 sector A simple spreadsheet can detect circumstances when this should be done Any quality of the composition that includes the proportion of elementary compositions requires this type of treatment. a good approximation by means of a linear combination even if it is not mathematically correct The computer 30 executes a prediction routine 76 of processing the currently correlated composition and quantity analyzes indicated by the data 68 with the aggregate composition data A " from the real-time database 74 to predict according to the compositions and quantities of the bulk materials that have been delivered to be stacked at a given position of the mixing bed, an aggregate composition p of the bulk materials in the respective sectors S of the mixing bed when the respective sectors S are recovered, and due to that process provides predictions of the composition aggregates p for the respective sectors S. In an alternative embodiment, the prediction routine 76 also processes delivery bread data 82 generated by the "delivery plan" routine 48 to perform the prediction of the composition of aggregate p according to the compositions and quantities of the bulk materials planned to be sent to the stack in the mixing bed. The delivery plan data 82 combines the position plan 44 and the selection plan 46 provided, by the routine "delivery schedule" 48. During the "delivery plan" routine 48, the computer 30 processes the composition predictions. of Ap aggregate calculated with. the data 84 indicating the desired aggregate composition Ao for the respective sectors S when the bulk material is recovered by comparing the calculated aggregate composition Ap for a selected sector S with a desired aggregate composition A0 for the selected sector S and when the predicted aggregate composition calculated Ap for the selected sector deviates from the desired aggregate composition A,,, the computer responds to the prediction of aggregate composition APu by stating that the stacking of a given bulk material given at a given position of the mixing bed would cause a given sector S of the mixing bed including in bulk material taken to the given position has an undesired aggregate composition when the given sector S of the mixing bed is recovered, by changing the position plan 44 and / or the selection plan 46 to cause the stacking of the bulk material delivered to be omitted a given position of the mixing bed at the given place of the mixing bed. j. = Ap = .Ay (equation 2) where ^ and A "represent respectively the lower and upper limits of the desired range of aggregate composition p. There may be several instances of equation 2 for each sector, there being one for each element or quality, for example LSF, proportion of silica, iron modulus etc. The computer 30 calculates a corrective quantity and composition of the bulk materials required to be deposited at a given position in order to correct the deviation. The composition C * of the undelivered bulk material that is required to cause the given sector to have a desired aggregate composition AD when the given sector S of the mixing bed is recovered is determined in accordance with the following: AD = CD * MD = CC * MC + CX * MX (equation 3) C ^ Cn ^ Cp (equation 4) where CD is the desired composition of the bulk material after recovery of sector S, MD is the desired mass of the bulk material after the recovery S, Cc is the current composition of the bulk material in the sector S, Mc is the current mass of the bulk material in the sector S, Mx is the mass of the bulk material for the sector S, CL and C "represent respectively the lower and upper limits of the desired range of the composition CD. As indicated above, qualities that are proportions of sums, such as LSF, must be obtained separately to calculate the percentage by weight of the constituent elements for the sector then calculate the LSF for sector S. If LSF, the silica module and other non-linear derivative quantities must be controlled, we must first solve a set of equations to determine the intervals of each of the element compositions that are required. Controlling the optimal composition of the materials when "optimal" is in terms of more than one quality parameter is complex, particularly when the controlled variables are strongly coupled, such that when the quality parameters are Inunctions of the same group of oxides. Several search strategies can be used to find the optimal solution for either the best mix of materials or the best material to finish a layer or sector subject to several practical constraints. A search strategy is based on the Simplex method, which is a linear programming technique to find an optimal point that is known to be at the intersection of two or more inequality constraints. Other search strategies that can be used are based on the Newton or quasi-Newton algorithm, which search based on the gradients. The base theory behind all these multi-variable techniques can be found in literature and in computer libraries, such as M ++ Class Library. Dyad Software's OPTIM optimization module can be used as the basis of a computer program for particular cases. There are also other computer software packages such as Matlab, which can be used to help solve problems that include linear programming. Experienced technicians familiar with linear programming generally have the knowledge necessary to solve problems of this type. In order to determine the volume of bulk material currently delivered that must be omitted from stacking at a given place in the mixing bed, the delivery plan routine 48 calculates the maximum volume VM of the correction material necessary to completely correct the composition of the sector. dices, using the aggregate composition data A "of the real-time database 74 and the composition ranges of the available bulk correction materials and causes the limited amount of bulk material currently delivered of at least that VM volume. The "plan, delivery" routine 48 also responds to predictions of undesirable aggregate composition Atj by changing the position plan 44 and / or the selection plan 46 to cause so that when less a corrective bulk material is stacked in the given point of the mixing bed after the omission in order to cause the given sectors S of the mixing bed to have a desired aggregate composition AQ when the sector S of the mixing bed is recovered. The composition C of the corrective bulk material required to cause a given sector to have a desired aggregate composition AD when the given sector S of the mixing bed is recovered, is determined in accordance with equations 3 and 4 taking into account the amount of Bulk material that was omitted from stacking at a given place in the mixing bed. When the material of the composition specified for the correction of the sectors of the mixing bed is available the stacker returns to the sectors not completed. As the stacker passes over and over again over the unfinished region of the delivered bulk material composition, it is continuously monitored in each sector to process the actual composition of the correcting material that is being stacked in the mixing bed and not what I anticipate according to the selection plan 46. It is important that a volume margin is left for subsequent correction in case the correction material is not exactly as I anticipated. The computer 30 is adapted to execute the aforementioned routines 48,62,66,70,76 by means of computer readable storage means 86 stored in the computer 30 and configured to cause the computer 30 to execute those routines. The present invention is also useful for selectively correcting irregularities in the composition of the aggregates in one or more given sectors of circular and non-circular mixing beds without interrupting the continuous construction of the mixing bed. * a planned model of construction of a mixing bed 88, with which the present invention is particularly useful as shown in Figures 7A and 7B. The bulk material is recovered in sections from the face 89 of the mixing bed 88 as shown in FIG. 7B, advancing in the directions shown by the arrow 90. The successively deposited layers of the mixing bed 88 are arbitrarily numbered from the 11, as shown in Figure 7B. The model of movement of the stacker depositing the layer number 7 is shown in figure 7A with solid lines, and the model of the movement of the stacker depositing the layer number 8 is shown with dotted lines. The position of the posx stacker (in the direction shown laterally in Figures 7A and 8A) provides the identity of the traversed sector. The position of the posy stacker provides a measure of the degree of finishing of the layer as well as the number of strips per layer. For this type of database-based mixing bed it can be subdivided in the direction and as in the x direction, the sectors extending through only a portion of the width of the mixing bed. Another predetermined model of the construction of a non-circular mixing bed, with which the present invention is particularly useful is shown in Figures 8A and 8B. The planned construction model of a non-circular mixing bed 92, with which the present invention is particularly useful is shown in Figures 8A and 8B. The bulk material is recovered in sections of the face 93 of the mixing bed 92, as shown in Figure 8B, the reclaimer advancing in the directions shown by the arrow 94. The successively deposited layers of the mixing bed 88 are numbered arbitrarily from 1 to 11, as shown in figure SB. The model of movement of the stacker to deposit the layer number 7 is shown in the figure SA by line solidad; and the model of movement of the stacker when depositing the layer number 8 is shown with dotted lines.

The present invention is also useful for selectively correcting irregularities in the aggregate composition in * one or more of the given sectors of a longitudinal mixing bed such as that shown in Figure 1, in which the stacker is moves forward and backward along the same spine while depositing bulk material. The mixed / sector / layer bed databases can be displayed in terms of class objects. Each object of the mixing bed consists of m sector objects and n layer objects. Also the material in each sector object consists of horizontal layer object material r, inclined layer objects s, and upper layer objects t. The mixed bed, and layer objects (that is, databases) are updated every new analysis. The attributes of each object (current weight, current chemistry, percentage of finished, etc.) are available for use during the prescription of layers and can also be monitored by the operator. Two belt scales can be provided to provide quantitative measurements for two different points along the conveyor in certain applications in which there are variable time delays between the composition analyzer and the stacker. With two scales and belts the correlation can be determined either between one or both measurements of the belt scale and the analysis of the bulk material. The stacker status measurements indicate whether the stacker is moving or not (this is the belt has material) or stopped (this is the belt is empty). The state measurement is used to improve the accuracy of the measurement of the quantity entered in the database during periods of interrupted flow. Other inputs to the computer 30 are provided by the operator, either in advance in real time, or are determined by default or by means of the sensor information. For example, layers can usually be inclined, but an operator could specify the number of horizontal lower layers and upper layers. This provides a flexible mixing bed configuration that includes any of the following, for example: 1. 8 horizontal layers. 8 inclined layers 3. 7 inclined layers 1 a horizontal background layer 4. 6 inclined layers with 2 horizontal layers of background 5. 5 inclined layers with 2 horizontal layers of background and 1 upper horizontal layer. The operator must enter the desired chemistry for the mixing bed and the feasibility limits on the prescribed chemistry. The limits of feasibility in prescribed chemistries are usually found in terms of percentages of oxides and represent the chemical range of material that can be found in the available sources of the bulk material. The correlation between the analysis of the bulk material and the quantity measurement is very important to have accurate database records. There is a first time delay Dtl between the quantitative measurement of a given sector of the bulk material by means of the belt scale on the conveyor belt of the bulk material analyzer. If the belt speed is not constant, the time delay Dtl must be adjusted. Since a composition analysis generally requires a minimum interval of time, for example one minute, the appropriate correlation at time t = tA requires an integrated quantity measurement in the time interval for the same material being analyzed. There are additional delays between when the material passes through the analyzer and when the compositional analysis signals are available for processing by the computer. Similarly there is a time delay when the material passes over the scale and when the quantitative measurement signals are available to the computer.

In addition, both the integration of the measurement data in that interval of time and the calculation of the analysis results of the composition measurement data introduce definable time delays. All these delays must be determined and a combined time delay is introduced with a delay filter such that the analysis interval and the weighing interval are properly synchronized. It is also very important to calculate the time delay Dt2 between the moment of the analysis of the composition and the moment when the material is placed in the mixing bed in order for the database to be accurate. The speed of the conveyor belt will be variable, particularly during the start and stop of the band. The length of the conveyor belt from the position of the analyzer to the position where the material leaves the stacker m to be placed in the mixing bed can also be variable. In any event, the time delay Dt2 can be calculated from the length of the known conveyor and the speed of the band. Although the details of how these time delays can be calculated can vary between systems, the objective is always to ensure that for each material composition analysis, the analyzed chemical composition of the material correlates with the final position of the material analyzed in the mixed bed. Figure 9 is a flowchart of an example of the algorithm logic followed by the computer 30 to determine the chemical prescription for the next layer. In this example it is assumed that a layer has a coherent chemistry. This can be useful when the chemistry of the layer can not be changed quickly. In general, the composition can be changed within a layer, allowing more freedom to precisely control the composition of the sector. As mentioned above, given the information previously described, the computer 30 updates the mixed bed, sector and layer objects each new analysis. The computer then has all the information necessary to determine the quantitatively weighted accumulated chemistry as well as the percent completion for each sector that is going to be traversed by the next deposited layer of bulk material. Finally, a prescription is calculated and for the next layer, the prescription is a function of the chemistry and percentage of completion of all the sectors that receive the material of the layer. The chemistry incorporates all the present layer even if it has not been finished yet. Because the prescription is provided every minute, it is possible to establish trends, which can provide early determination of the preferred chemistry of the next layer by observing the convergence of the chemistry of the layer or sector with the target. Assuming that a typical layer requires ten to fifteen minutes to form and the selected source of material takes fifteen to twenty minutes to be available to feed the stacker once the prescription is started, the prescription can take effect one to three layers after . With the prescription of each minute and assuming that the chemistry of the present layer does not vary widely there must be sufficient time to determine the proper chemistry of the next layer while maintaining an efficient operation of feeding the selected bulk material from its sources. The algorithm of Figure 9 implements a strategy that ensures that the layer proscriptions are within feasible limits as of the material available and (assuming that the proscriptions are met) results in the present and future sectors fulfilling the desired chemistries. For a given group of quantities and qualities of sector and a desired chemistry, which is shared by all sectors, and knowing the impact of the next layer on all sectors in terms of quantity for a case in which the chemistry is almost constant For each layer, two different methods that can be used to optimize the prescription of n sectors of a future layer will be described. In a method, the variable n provides an aggression factor and may or may not equal the number of sectors affected by the layer in question. In the second method, the variable n is determined and used as a performance index to calculate how much margin is obtained with the prescription. In both methods, the algorithm in Figure 9 calculates the proscriptions of several layers in the future. For example, if the R layer is the next necessary layer of a prescription, the algorithm bases the optimized prescription of the R layer on part of the projected chemistry of the S layers., T and U. In a similar way the algorithm bases the optimized prescription of the S layer partly in the updated projected chemistry of the T, U and V layers. Two critical points related to each method are (a) all prescription chemical la and projected are restricted to the feasibility of chemistry provided by the operator, and (b) it is assumed that success is a discrete measure.

For example if the chemistry of a sector falls within desired limits, then the success is TRUE - true otherwise it is FALSE - false. In the first strategy, the computer 30 is programmed to provide the prescription that allows future proscriptions to maximize its distance from the feasible limits. In the second method, the computer 30 is programmed to achieve the "perfect chemistry" for each sector on the horizon and the computer 30 determines how many layers in the future (n) are needed before the chemistry of the required layer violates the limits of feasibility. For both strategies, the question remains as to how to weigh a prescription in terms of the sectors that are directly affected by the layer. For example, layer R can complete sector 6, but sector 7 lacks an additional layer. Sector 8 has two additional layers, etc. Since sector 6 lacks a layer to finish, it can be difficult in some cases impossible to finish the sector within the desired range of chemistry. In general, as a given sector approaches its limits of feasibility, greater weight must be given to have the best opportunity to stay within feasible limits. These limits depend on the number of layers that still have to be placed in the sector, how close the composition is to the defined restrictions, and the correction material available. In some cases if a sector approaches or exceeds the feasibility limit it may be necessary to give that sector most or all of the weighing in order to stay within or at least close to the desired restrictions. The range limits of the desired chemistry provide the constraints for the optimization process for future layers. A preferred optimization process uses a search algorithm based on the Simplex method. This method allows the algorithm to quickly identify all feasible points at the extremes. The extreme feasible points are those along the outer surface of the feasibility space. The fundamental theory behind the Simplex method is that the optimal solution is located on that surface, this can be explained in the following way: imagine a volume that is restricted by a group of parameters (chemistry in this case). All points within the volume make up the "solution space" and are called feasible because they satisfy all restrictions. The simple method states that the optim solution, necessarily leads to the extreme at least one restriction and therefore is located on the surface of the volume. The search algorithm consists of a series of linear algebra steps called pivstation, in which the connections between extremity feasibility points are moved in search of all the points that satisfy a criterion. Once the list of feasibility points has been identified, the distribution is made to identify the unique optimized description. Figure 10 illustrates the use of the present invention when constructing a mixing bed 10 with bulk material 96 obtained from a quarry 97. Bulk material 96 is delivered by vehicles 98.99 from the quarry 97 to a crusher 100, from which the crushed bulk material is transported by means of a conveyor 102 to a stacker 12. On the route to the stacker 12, the bulk material 96 is weighed by means of a belt scale 40. adjacent to the conveyor belt 102 and the composition of the bulk material is analyzed by means of a PGNAA analyzer 38, through which the band 102 passes.

The signals of quantity (weight) measurements 56 of the belt scale 40 and the composition analysis signals (spectra) 54 of the analyzer 38 are provided to the computer 30, where they are processed with the delivery rate signals (speed of the belt) 52 from the delivery rate monitor 36, the position signals of the stacker 50 from a stacking control 104 and user input signals 84 specifying an objective compositional quality and the requirements of the mixing bed to thereby provide a delivery position plan 44 to stacking control 104 and a material selection plan 46 to quarry 97, as described above with reference to Figure 5. As an option, a desulfurization request plan 46a can be provided to a desulphurization tank 108, from which different bulk materials are selectively provided on the conveyor belt 102 in order to provide the desired mixture of bulk materials to be stacked in the mixing bed 10. The advantages specifically described herein do not necessarily apply to any conceivable embodiment of the present invention. In addition, these advantages of the present invention are only examples and should not be construed as the only advantages of the present invention. While the foregoing description contains many specificities, these should not be construed as limitations of the scope of the present invention, but rather as examples of the preferred embodiments described herein. Other variations are possible and the scope of the present invention should be determined not only by the modalities described herein but by the claims and their legal equivalents.

Claims (9)

1. - A system for constructing a mixing bed of variable bulk materials, from which sections of bulk materials are periodically recovered, consisting of: means for constructing a mixing bed composed of many layers of variable bulk materials when stacking varied bulk materials delivered in the mixed bed at different points according to a plan; means for analyzing the composition of the bulk materials that are being received for stacking in the mixing bed; means for measuring the quantities received of bulk materials to be stacked in the mixing bed; means for correlating composition analyzes and quantity measurements with the different places to which the bulk materials are taken to stack them; and means adapted to process the composition analyzes and the quantitative measurements with the position correlations to predict, according to the compositions and quantities of the bulk materials that are being carried to stack them in the mixing bed, an aggregate composition of bulk materials in respective sectors of the mixing bed when the respective sectors are recovered.

2. A system according to claim 1, further comprising: means adapted to respond to predictions of the aggregate composition indicating that the stacking of a given bulk material at a given place in the mixing bed would cause a given sector of the mixing bed including the given bulk material brought to the given point has an undesired aggregate composition when the given seetor of the mixing bed is recovered, causing the omission of the stacking of the conducted bulk material given in the given place of the mixing plate

3. - a system for building a mixing screen of variable bulk materials, from which sections of the bulk materials are periodically recovered, consisting of: means for building a mixed mixing screen layers of variable bulk materials when stacking the various bulk materials delivered to the mixing bed at different points according to a plan; means for analyzing the composition of the bulk materials that are being received for stacking in the mixing bed; means for measuring the quantities received of bulk materials to be stacked in the mixing bed; means for correlating composition analyzes and quantity measurements with the different places to which the bulk materials are taken to stack them; and means adapted to process the compositional analyzes and the quantitative measurements with the position correlations to provide a real-time database of the current composition of the bulk materials in respective sectors of the mixing read.

4. - A system according to claim 3, further comprising: means adapted to compensate for the characteristics of different types and / or sizes of materials within the bulk material stacked at a given position by knocking respectively at different distances from the given distance towards a mixing bed edge when adjusting the database in real time according to the collapsing characteristics.

5. - A system according to claim 3, further comprising: means for processing the composition analyzes and quantity measurements with the current correlations and the real-time database for predicting aeuerds with the compositions and amounts of the bulk materials that have been delivered to be stacked in a given position of the mixing bed, an aggregate composition of the bulk materials in the respective seetsres of the mixing bed when the respective seetsres are recovered.

6. - A system to be used in a method to build a mixing bed composed of several layers of variable bulk materials, from which sections of the bulk materials are periodically recovered, the method includes the steps of constructing a compound mixing bed of many variable bulk materials when stacking the bulk materials delivered in the mixing bed at different points according to a plan; analyze the composition of the bulk materials that are being received to be stacked in the mixing leeho; measure the quantities received of bulk materials to be stacked in the mixing bed; correlate the compositional analyzes and quantity measurements with the different places to which the bulk materials are carried to stack them; The system eonsiste.de adapted means to process compositional analysis and quantitative measurements with position correlations to predict, according to the compositions and quantities of bulk materials that are being carried to stack them in the mixing bed, a aggregate composition of the bulk materials in respective sectors of the mixing leeho when the respective sectors are recovered: and means adapted to respond to aggregate composition predictions that indicate that the apilamients of a bulk material given at a given location The mixing of the die would cause a given set of the mixing bed including the given bulk material taken to the given point to have an undesired aggregate composition when the given value of the bed of ezelads is recovered, when provoking the omitting of the conducted bulk material given in the given place of the mixed bed.

7. - A system according to claim 2 to 6, which "further consists of: means adapted to respond to the prediction of undesired aggregate composition by causing at least one bulk correction material to be stacked in the given location of the After the omission, it is proposed that said member of the mixing leeho have a desired aggregate composition when the given sector of the mixing bed is recovered

8. A system according to claim 1, 3 or 6, in which the sectors are approximately vertical 9.- a system according to claim i, 3 ß 6, in which the sectors at an angle corresponding to the angle at which the sectors are recovered. A method for constructing a mixing bed of variable bulk materials, from which periodic recoveries of bulk materials are recovered, which consists of the steps of: (a) building a mixing bed composed of many layers of variable bulk materials when stacking the various bulk materials delivered to the mixing bed at different points according to a plan; (b) analyze the composition of the bulk materials that are being received to be stacked in the mixing bed; (c) measure the quantities received "of bulk materials to be stacked in the mixing bed, - (d) correlate the analysis of quantity and the quantity measurements in the different places to which the bulk materials are carried to stack them, and (e) process the composition analyzes and the quantitative measurements are the position variables to predict, according to the volumes and quantities of the bulk materials that are being carried to stack them in the mixing bed, a composition of aggregate of the bulk materials in respective sectors of the mixing bed when the respective sectors are recovered 11. A method according to claim 10, further comprising the step of: (f) responding to the predictions of the Aggregate composition indicating that the stacking of a given bulk material at a given location in the mixing bed would cause a given sector of the mixing bed to include The given bulk material brought to the given point has an undesired aggregate composition when the given sector of the mixing bed is recovered, by causing the stacking of the given bulk material given at the given location of the mixing bed to be omitted. 12. A method according to claim 11, further comprising the step of: (g) responding to that prediction of unwanted aggregate composition by causing at least one bulk correction material to be stacked at the given location of the bed of mixed after the omission in order to cause that sector of the mixing bed to have a desired aggregate composition when the given sector of the mixing bed is recovered. 13. - A method to build a mixing bed of variable bulk materials, from which sections of the bulk materials are periodically recovered, consisting of the steps of: (a) building a mixing bed composed of many layers of variable bulk materials when stacking the bulk materials delivered to the mixing bed in different points according to a plan; (b) analyze the composition of the bulk materials that are being received to be stacked in the mixing bed; (c) measuring the quantities received of bulk materials to be stacked in the mixing bed; (d) correlate composition analyzes and quantity measurements with the different locations to which the bulk materials are taken to stack them; and (e) process the composition analyzes and the quantitative measurements with the position correlations to provide a real-time database of the current composition of the bulk materials in respective sectors of the mixing bed. 14.- n method according to claim 13, further comprising the step of: (f) compensating the characteristics of different types and / or sizes of materials within the stacked bulk material at a given position by knocking respectively at different distances from the given distance towards an edge of the mixing bed when adjusting the database in real time according to the characteristics of collapse. 15. - A method according to claim 13, further comprising the step of: (f) processing the composition analyzes and quantity measurements with the current correlations and the real-time database to predict according to the compositions and quantities of the bulk materials that have been delivered to be stacked at a given position of the mixing bed, an aggregate composition of the bulk materials in the respective sectors of the mixing bed when the respective sectors are recovered. 16. A method according to claim 10 or 13, in which the sectors are approximately vertical. 17. - A method according to claim 10 or 13, wherein the sectors at an angle corresponding to the angle at which the sections are recovered. 18. - A computer readable storage medium for use in a computer used in a method for constructing a mixing bed composed of many layers of variable bulk materials when stacking the variable bulk materials received in the mixing bed at different points according to a plan; analyze the composition of the bulk materials that are being received to be stacked in the mixing bed: measure the quantities received of bulk materials that are going to be stacked in the mixing bed; and correlating composition analyzes and quantity measurements with the different locations to which bulk materials are taken to stack them, where the storage medium is configured to cause the computer to process compositional analyzes and quantitative measurements with the position correlations to predict according to the compositions and quantities of the bulk materials that have been delivered to be stacked at a given position of the mixing bed, an aggregate composition of the bulk materials in the respective sectors of the mixing bed when the respective sectors are recovered. 1

9. - A storage medium according to claim 18, further configured to cause the computer to respond to aggregate composition predictions that indicate that the piling of a given bulk material at a given place in the mixing bed would cause that a given sector of the mixing bed including the given bulk material brought to the given point has an undesired aggregate composition when the given sector of the mixing bed is recovered, by causing the stacking of the conducted bulk material given in the given place of the mixing bed. 20. A storage medium according to claim 19, further configured to cause the computer to respond to that prediction of undesired aggregate composition by causing at least one bulk correction material to be stacked at the given location of the mixing bed. after of the omission in order to cause that sector of the mixing bed to have a desired aggregate composition when the given sector of the mixing bed is recovered. 21. A computer-readable storage medium for use in a computer used in a method for constructing a mixing bed composed of many layers of variable bulk materials by stacking the variable bulk materials received in the mixing bed at different points. according to a 'plan; analyze the composition of the bulk materials that are being received to be stacked in the mixing bed: measure the quantities received of bulk materials that are going to be stacked in the mixing bed; and correlating composition analyzes and quantity measurements with the different locations to which bulk materials are taken to stack them, where the storage medium is configured to cause the computer to process compositional analyzes and quantitative measurements with the position correlations to provide a real-time database of the current composition of the bulk materials in respective sectors of the mixed-bed. 22. A storage medium 1 according to claim 21, further configured to cause the computer to process composition analyzes and quantity measurements with the current correlations and the real-time database to predict according to the compositions and quantities of the bulk materials that have been delivered to be stacked at a given position of the mixing bed, an aggregate composition of the bulk materials in the respective sectors of the mixing bed when the respective sectors are recovered. 23. A method according to claim 18 or 21, in which the sectors are approximately vertical. 24. A method according to claim 18 or 21, in which the sectors at an angle corresponding to the angle at which the sections are recovered 25. A system for constructing a mixing bed of materials a Bulk variables, from which sections of the bulk materials are periodically recovered, consisting of: a stacker to feed the bulk materials and to deposit the bulk materials fed in a plurality of different points of a mixing bed to sequentially form a plurality of stacked layers of bulk materials throughout the mixing bed; a locator of the stacker to provide a position signal that indicates the position in which the apiiadora is depositing the material in bulk; a composition analyzer for determining a composition of the bulk materials being fed by the stacker and providing a composition signal indicating the determined composition; a quantitative measuring system for measuring a quantity of the bulk materials that are being fed by the stacker and for providing a quantity signal indicating the quantity measured; and a computer coupled to the locator of the stacker, the composition analyzer and the quantity measurement system to receive the position signal, the composition signal and the quantity signal, where the computer is adapted to process the signal of position, the composition signal and the quantity signal to correlate the position in which the stacker deposits the bulk material with the composition and quantity of the bulk material that is being deposited at that location and to calculate an aggregate composition which was predicted from the bulk materials within a selected sector of the mixing bed formed by the deposit of the bulk material in that position. 26. A system according to claim 25, wherein the computer is further adapted to compare the aggregate composition calculated for a selected sector with a desired aggregate composition for the selected sector and when the predicted aggregate composition calculated for the selected sector deviates from the desired aggregate composition, to communicate a signal that causes the stacker to bypass the deposit of the bulk materials fed at that point of the mixing bed during the deposit of at least one subsequent layer in the bed of mixed. 27. A system according to claim 26, in which the computer is also adapted to calculate the quantity and composition of corrective bulk materials that need to be deposited at that point to correct the deviation and to communicate that causes the Stacker deposits the quantity and composition of corrective bulk materials in the place of the mixed bed where the deposit was omitted.