What is a HGI indicator?

<p id="isPasted">Hardgrove Grindability Index (short HGI) is a measure for the grindability of coal. Grindability is an index, therefore it has no unit. The smaller the HGI, the harder is coal texture and less grindable is the coal.</p><p>Grindability is an important factor for the design a coal mill. As grindability depends on many unknown factors, HGI is determined empirically using a sample mill according to the following procedure:</p><p id="isPasted">50 g of air dried coal featuring a grain size in the range between 0.6 and 1.18 mm are filled into the sample mill and a weight is put on the mill's grinding stone. After 60 rounds the grinded coal is put on a sampling sieve. Factor D equals the fraction of the coal passing through the sieve of 74 ?m corresponding to 200 mesh. HGI is calculated from D as follows:</p><p>H = 13 + 6.93 ?D</p><p>This procedure only results in relative values because the sampling mill is calibrated using a reference coal. The HGI of the reference coal is defined as 100.</p>

<p id="isPasted">In the context of trading, the HGI indicator (Highway Grail Indicator) is a popular technical tool designed to simplify market analysis by combining multiple data points into easy-to-read visual signals.&nbsp;</p><p><strong>What is it?</strong></p><p>The HGI is not a single calculation but an amalgamation of several indicators. It is primarily used on MetaTrader 4 (MT4) to help traders identify whether the market is trending, ranging, or reversing at any given moment.&nbsp;</p><p>Its core goal is to provide a comprehensive "read" of the market to answer critical questions:&nbsp;</p><ul><li>Trend Status: Should I follow the current trend or prepare for a range?</li><li>Trade Direction: Which way should I trade this specific market?</li><li>Trade Management: When should I take profits or look for a reversal?&nbsp;</li></ul><p><strong>Common HGI Signal Types</strong></p><p>The indicator typically displays various arrows and icons on the chart to represent different market conditions:&nbsp;</p><ul><li>Trend Signals (Big Arrows): Indicate strong directional momentum.</li><li>Range Signals (Small Arrows): Suggest the market is consolidating or trading within a defined range.</li><li>RAD Signals (Diagonal Arrows): Represent specific trade alerts internally calculated by the script.</li><li>Trend/Range Waves: Coloured waves on the chart that visually define the current market regime.&nbsp;</li></ul><p><strong>Key Features for Traders</strong></p><ul><li>Multi-Timeframe Support: Advanced versions, such as the HGIMatrix, allow you to monitor signals across up to five different timeframes simultaneously in a single dashboard.</li><li>Non-Repainting: The standard version is designed so that historic signals do not change once they are established, providing reliable backtesting data.</li><li>Customizable Alerts: It can send notifications via MT4 pop-ups, mobile push notifications, or log them to a file.&nbsp;</li></ul><p><strong>Other Uses of "HGI"</strong></p><p>Outside of trading, HGI can refer to:</p><ul><li>Hardgrove Grindability Index: A standard measure used in the energy industry to determine how easily coal can be crushed.</li><li>Hemoglobin Glycation Index: A medical metric used to predict the risk of complications in patients with diabetes.&nbsp;</li></ul>