Selection and optimization of the substrate in constructed …
The hardness is low (Platts hardness: 1– 3), and the particles are fragile. The hydraulic permeability coefficient is relatively small: 1 × 10 −13 – 2 × 10 −9: ... The characteristics of the selected substrate include high porosity and permeability coefficient, stable chemical properties, strong decontamination ability, etc., which ...
Natural fractures in soft coal seams and their effect on …
The Xinyuan Coal Mine is a typical coal and gas outburst mine, with an original gas pressure in the range of 1.24–2.44 MPa, a gas content in the range of 11.77–14.89 m 3 /t, porosity of 3.49%, coal hardness coefficient of 0.21–0.36, initial velocity index of gas emission in the range of 15.5–21.8 mm Hg, and coal seam permeability ...
Specifications Guide Global Iron Ore
The global Iron Ore specifications guide contains the primary specifications and methodologies for Platts Iron Ore global catalogue of price assessments. The various sections of this guide are designed to give S&P Global Commodity Insights subscribers as much detail as possible about a wide range of methodology and specification issues.
What Is Mohs Hardness Scale and How Does It Work?
A good example is the kyanite mineral. Its hardness can be 5.5 or 7.0, depending on the axis of your scratch. Therefore, it is good to test various crystal faces or directions before concluding. 4. More hardness tests – Vickers, Brinell, Rockwell, Shore, and Knoop. Hardness is the ability of a material to resist abrasions (scratching) or ...
Platts Price Benchmarks
In today's rapidly changing market, Platts bring price transparency through its respected price assessments and benchmarks. Our robust methodologies ensure consistency and integrity, setting the standard for price discovery across commodities, from established to emerging markets, and with over 100 years of expertise. ...
Technical Handbook O-rings 5. Designing with Rubber
thickness of 0,25 in. (6 mm.). Always use standard hardness discs 1.28 in. diam. by 0,25 in. thick (ø32 x6 mm.), or 6 in.x 6 in.x 0.075 in. (150x150x2 mm.) sheets piled up to a minimum of 0,25 in. (6 mm.) to determine durometer hardness. It has been almost impossible to obtain reliable and reproducible hardness readings on
Research on the Development of Hydraulic Flushing …
The flushing effect also will be very low when the Platts coefficient of coal near the flushing hole is very high. ... Generally, coal with high hardness is commonly considered to be a non-outburst risk; however, several coal mines with hard coal seams in China have experienced coal and gas outbursts. Coals with different degrees of ...
Polyurethane Technical Data
With the ability to be formed into practically any shape, size, and hardness, polyurethanes are extremely versatile. (800) 833-9960 / (828) 287-7030 info@sunray-inc. How to Order; Feedback; FAQs; My Account; 0 Items. Home; ... Polyurethanes can be formulated with coefficients of friction varying from very low, for items like bushings ...
SYL Type PC200 Tip Point 20Y-70-K4030
1, the mining object high hardness (Platts hardness coefficient =16 18), the material block degree (weight>500 kgaccounted for 30%), the Qing (eating) foundation work, this is the worst condition. As in Lianyungangportconstruction, mining rock are gneissic granite, bucket teeth service life is very short, only 8 – 12 days.
Deformation mechanism and control technology of gob-side …
2–2 coal is asphalt, the luster is mainly semi-bright coal, the thickness of the coal seam at the working face is about 2.04–2.56 m, the average thickness is 2.3 m, the Platts hardness coefficient of the coal seam is f = 1.0, and the …
Numerical analysis of influencing factors of steeply inclined …
The Platts hardness factor of coal seam is less than 1 (f < 1), and the structure is simple. The inclination angle is between 27° and 55°, with an average of 45°. The coal quality …
Hardening Coefficient
The example of 〈110〉 copper single crystals deformed in stage II is described first. In this double slip orientation, the well known stages II and III are observed as stress increases, as illustrated in Figure 9.21.The hardening coefficient is constant along stage II with a value close to 185 MPa, which corresponds to θ/μ. close to 1/230 (μ is the shear modulus).
Platts Assessments Methodology Guide
Platts for clarification of data that has been published, or to share a complaint. It also describes how to find out more about Platts complaint policies. Platts separately publishes a list of detailed specifications for the trading locations and products for which Platts publishes assessments for a particular commodity, which can be found
(PDF) Modern Methods and Tools for Determining …
Since the coefficient of hardness mainly reflects only fracturing under compressive loads, and in real conditions tensile and shearing forces are often used, it becomes necessary to introduce ...
Discussion on Crushing Theory in Gold Processing …
The crushability coefficient and grindability coefficient of the ore proposed in combination with the crushing and grinding technology not only reflect the firmness of the ore, but also can be used to quantitatively measure …
20Y-70-K4030 SYL TIP LONG PC200 fits …
1, the mining object high hardness (Platts hardness coefficient =16 18), the material block degree (weight>500 kgaccounted for 30%), the Qing (eating) foundation work, this is the worst condition. As in …
Correlation between hardness coefficient, specific …
Figure 1 shows a graph of the relationship between the minimum specific drilling energy and the hardness coefficient according to Protodyakonov. ...
Methodology and Specifications Guide
Platts is constantly reevaluating this model, discussing industry feedback and trends to make the Platts Analytics Yields and Netbacks valuations more accurate. Where Platts Analytics Yields and Netbacks can be found Platts Analytics Yields and Netbacks calculations are produced every day for all locations. They are available through several
anchor drill rigs equipment crawler model drilling rig for …
With advantages such as concise and compact structure, safe and reliable, short auxiliary time, flexible response, operate and maintain simple and convenient etc. Drilling rock in ideal drilling speed among Platts hardness coefficient f=6~15. 3.
Numerical analysis of influencing factors of steeply inclined …
The Platts hardness factor of coal seam is less than 1 (f < 1), and the structure is simple. The inclination angle is between 27° and 55°, with an average of 45°. ... a 13 are polynomial coefficients, constants, as shown in Table 3. Table 3 Polynomial coefficient values of coal face displacement prediction model. Full size table.
CMM capture engineering challenges and characteristics of in-situ stress distribution in deep level of Huainan coalfield
The rock firmness coefficient (also known as the Platts coefficient) proposed by Protokyakonov is still widely used in mining operations and exploration and tunneling …
Prediction method of cutting stability of roadheader based …
where K 1 = 0.25 P k K t K s K a + 0.1 P k S T, K 2 = 0.018 P k K t K s K a β, K 3 = 2.5 × 0.15 + 0.00056 P k; P k = 44 f 3 2, f is the Platts hardness coefficient of rock; K t = Type factor for picks, 1.5 for tapered teeth, and 1 for cutter teeth; K s = Pick shape correlation coefficient, k s k ts k ts ′ k td, t a p e r e d t e e t h k b k ...
Study on the Fracture Evolution Characteristics of Overlying …
The Platts hardness coefficient of #15 coal is f = 0.17~0.8, the recoverable index is 1.0, the coefficient of variation of coal seam thickness is 12.93%, the thickness of coal seam is 4.1~6.5 m, the average thickness is 5.2 m, and the thickness of the coal seam is stable. The dip angle of the coal seam is 5~14°, with an average value of 8°.
[Retracted] Study on Dynamic Evolution of
MahdevariandMoarefvand proposed that the hardness of coal was the biggest influencing factor on rib spalling [22 ... with a compressive strength of about 11.3 ∼ 13.2 MPa and a Platts coefficient of about 1.32, which is of low firmness and belongs to the unstable type; The immediate roof is gray-white fine-grained sandstone, with a compressive ...
Fabrication of diamond enhanced WC-Ni composites by …
In the test, the hard granite, a kind of solid and compact rock with the Platts hardness coefficient of 15–17, was selected as the grinding material. The mass loss of the …
Revisiting Protodyakonov's Pressure Arch Theory
is the hardness coefficient of pea stones and equals 2, the friction angle $ is taken from . table 2. The calculation results of each method (including the height of NBA formed by .
Specifications Guide Europe and Africa Refined Oil Products
The Europe and Africa Refined Oil Products Guide by S&P Global Commodity Insights contains the primary specifications and methodologies for Platts European Products assessments. The various components of this guide are designed to give our subscribers as much information as possible about a wide range of methodology and specification issues.
How to choose the model of crawler DTH drilling rig (One)?
Different rocks have different hardness indexes and drillability are also different. Ruggedness is often used to indicate how easy it is to break a rock. The size of the firmness is expressed by the firmness coefficient. The firmness coefficient is also called the hardness coefficient, which is also called the Platts hardness coefficient f value.
Adaptability Analysis of Full Height Mining at One Time of …
At present, the technology of full height mining at one time of shallow coal seams in China is mature, and its application is mainly concentrated in western mining areas, for example, the fully mechanized working face with large mining height of 1-2 coal seams in 12,401 working face of Shangwan Coal Mine in Shendong Mining Area (Xu et al., 2020 ...