【Weekly Topic】(32) June 21, 2015: How to take samples from a coal pile?

1. Sampling method from coal piles 　　Whether the coal pile has a regular or irregular shape, a surface must be selected as the sampling surface when taking coal samples. Start marking from 0.5 meters above the bottom of the pile. Draw a horizontal line every 1 meter upward, and draw a vertical line every 1 meter from one side of the sampling area to the other; this will result in several intersection points of horizontal and vertical lines across the entire sampling area. Sample collection points are selected from these several intersection points. The selected method is: the intersection points of odd-numbered horizontal lines with odd-numbered vertical lines, as well as those of even-numbered horizontal lines with even-numbered vertical lines, are all the points from which samples are taken. 　　When the selected samples are connected point by point, they appear to be several overlapping plum blossom petals. Therefore, such a sampling method is called plum blossom sampling. 　　2. The excavation depth should be 0.4 meters; coal from the surface of the coal pile should not be used as samples. Because the coal on the surface of the pile undergoes varying degrees of oxidation in the air, its properties also change gradually. The mass of each sample shall be no less than 2 kilograms. The usage angle of the sampling shovel is perpendicular to the surface of the coal pile. When encountering gangue, large pieces, or pyrite, they should not be discarded casually.

It is quite difficult to take coal samples from a coal pile. Due to the oxidation and weathering of the coal on the surface of the coal pile, as well as the influence of air humidity, the moisture content and degree of oxidation of the coal in the lower layers of the pile differ from those in the surface layer. Coal piles that have been left in place for a long time may also see an increase in foreign minerals in the surface layer of coal, thereby raising the ash yield. Furthermore, due to the effect of segregation, during stacking, large pieces of coal and gangue accumulate at the surface and the bottom of the pile, while the finer particles gather in the upper layers and the center of the pile, thereby increasing the unevenness in the quality of the coal within the pile. Furthermore, since the coal in the coal yard is constantly being taken out and brought in, the ash content of each batch of coal brought in varies. This will result in inconsistencies in the ash content of the coal within the stack. At the sampling site, the 0.1-meter-thick surface layer of coal should be removed first, and then sampling should be carried out while digging. Typical coal storage areas are not very spacious, making it impossible to store the coal in separate piles based on its type or grade during unloading. Over time, the quality of coal in the piles became increasingly complex. To ensure that the coal sample represents the overall characteristics of the entire coal pile as accurately as possible, it is necessary to select several sub-sample locations over a large area in a uniform manner. Methods for taking coal samples from a coal pile: 1. Sampling method from a coal pile: Whether the coal pile is regular in shape or not, a surface must be selected as the sampling surface when taking coal samples. Start marking from 0.5 meters above the bottom of the pile. Draw a horizontal line every 1 meter upward, and draw a vertical line every 1 meter from one side of the sampling area to the other; this will result in several intersection points of horizontal and vertical lines across the entire sampling area. Sample collection points are selected from these several intersection points. The selected method is: the intersection points of odd-numbered horizontal lines with odd-numbered vertical lines, as well as those of even-numbered horizontal lines with even-numbered vertical lines, are all the points from which samples are taken. When the selected samples are connected point by point, they appear to be several overlapping plum blossom petals. Therefore, such a sampling method is called plum blossom sampling. 2. The excavation depth should be 0.4 meters; coal from the surface of the coal pile should not be used as samples. Because the coal on the surface of the pile undergoes varying degrees of oxidation in the air, its properties also change gradually. The mass of each sample shall be no less than 2 kilograms. The usage angle of the sampling shovel is perpendicular to the surface of the coal pile. When encountering gangue, large pieces, or pyrite, they should not be discarded casually.

Adopt the coal sample method. 1. Sampling method from coal piles: Whether the coal pile has a regular or irregular shape, a surface must be selected as the sampling surface when taking coal samples. Start marking from 0.5 meters above the bottom of the pile. Draw a horizontal line every 1 meter upward, and draw a vertical line every 1 meter from one side of the sampling area to the other; this will result in several intersection points of horizontal and vertical lines across the entire sampling area. Sample collection points are selected from these several intersection points. The selected method is: the intersection points of odd-numbered horizontal lines with odd-numbered vertical lines, as well as those of even-numbered horizontal lines with even-numbered vertical lines, are all the points from which samples are taken. When the selected samples are connected point by point, they appear to be several overlapping plum blossom petals. Therefore, such a sampling method is called plum blossom sampling. 2. The excavation depth should be 0.4 meters; coal from the surface of the coal pile should not be used as samples. Because the coal on the surface of the pile undergoes varying degrees of oxidation in the air, its properties also change gradually. The mass of each sample shall be no less than 2 kilograms. The usage angle of the sampling shovel is perpendicular to the surface of the coal pile. When encountering gangue, large pieces, or pyrite, they should not be discarded casually.

Whether for coal piles with regular or irregular shapes, a surface must be selected as the sampling surface when taking coal samples. Start marking from 0.5 meters above the bottom of the pile. Draw a horizontal line every 1 meter upward, and draw a vertical line every 1 meter from one side of the sampling area to the other; this will result in several intersection points of horizontal and vertical lines across the entire sampling area. Sample collection points are selected from these several intersection points. The selected method is: the intersection points of odd-numbered horizontal lines with odd-numbered vertical lines, as well as those of even-numbered horizontal lines with even-numbered vertical lines, are all the points from which samples are taken. When the selected samples are connected point by point, they appear to be several overlapping plum blossom petals. Therefore, such a sampling method is called plum blossom sampling.

Plum blossom sampling method: Whether the coal pile has a regular or irregular shape, a surface must be selected as the sampling surface when taking coal samples. Start marking from 0.5 meters above the bottom of the pile. Draw a horizontal line every 1 meter upward, and draw a vertical line every 1 meter from one side of the sampling area to the other; this will result in several intersection points of horizontal and vertical lines across the entire sampling area. Sample collection points are selected from these several intersection points. The selected method is: the intersection points of odd-numbered horizontal lines with odd-numbered vertical lines, as well as those of even-numbered horizontal lines with even-numbered vertical lines, are all the points from which samples are taken. When the selected samples are connected point by point, they appear to be several overlapping plum blossom petals. Sampling quantity: The pit should be dug to a depth of 0.4 meters, and coal on the surface of the coal pile should not be used as samples. Because the coal on the surface of the pile undergoes varying degrees of oxidation in the air, its properties also change gradually. The mass of each sample shall be no less than 2 kilograms. The usage angle of the sampling shovel is perpendicular to the surface of the coal pile. When encountering gangue, large pieces, or pyrite, they should not be discarded casually.

That covers most of it. As a supplementary point, when sampling non-new surfaces, the surface layer of 0.2M thickness should be scraped off first before proceeding with sampling.

Sampling method from coal piles: It is relatively difficult to take coal samples from coal piles. Due to the oxidation and weathering of the coal on the surface of the coal pile, as well as the influence of air humidity, the moisture content and degree of oxidation of the coal in the lower layers of the pile differ from those in the surface layer. Coal piles that have been left in place for a long time may also see an increase in foreign minerals in the surface layer of coal, thereby raising the ash yield. Furthermore, due to the effect of segregation, during stacking, large pieces of coal and gangue accumulate at the surface and the bottom of the pile, while the finer particles gather in the upper layers and the center of the pile, thereby increasing the unevenness in the quality of the coal within the pile. Furthermore, since the coal in the coal yard is constantly being taken out and brought in, the ash content of each batch of coal brought in varies. This will result in inconsistencies in the ash content of the coal within the stack. So how can we ensure that the coal samples taken are sufficiently representative? At the sampling site, the 0.1-meter-thick surface layer of coal should be removed first, and then sampling should be carried out while digging. Typical coal storage areas are not very spacious, making it impossible to store the coal in separate piles based on its type or grade during unloading. Over time, the quality of coal in the piles became increasingly complex. To ensure that the coal sample represents the overall characteristics of the entire coal pile as accurately as possible, it is necessary to select several sub-sample locations over a large area in a uniform manner. The method for determining the sampling location is the coal sampling method from the coal pile, which will be described below. 　　1. Sampling method from coal piles 　　Whether the coal pile has a regular or irregular shape, a surface must be selected as the sampling surface when taking coal samples. Start marking from 0.5 meters above the bottom of the pile. Draw a horizontal line every 1 meter upward, and draw a vertical line every 1 meter from one side of the sampling area to the other; this will result in several intersection points of horizontal and vertical lines across the entire sampling area. Sample collection points are selected from these several intersection points. The selected method is: the intersection points of odd-numbered horizontal lines with odd-numbered vertical lines, as well as those of even-numbered horizontal lines with even-numbered vertical lines, are all the points from which samples are taken. 　　When the selected samples are connected point by point, they appear to be several overlapping plum blossom petals. Therefore, such a sampling method is called plum blossom sampling. 　　2. The excavation depth should be 0.4 meters; coal from the surface of the coal pile should not be used as samples. Because the coal on the surface of the pile undergoes varying degrees of oxidation in the air, its properties also change gradually. The mass of each sample shall be no less than 2 kilograms. The usage angle of the sampling shovel is perpendicular to the surface of the coal pile. When encountering gangue, large pieces, or pyrite, they should not be discarded casually.