What is dredging in gold mining?
1 Answer
Leave an answer
You must login to add an answer.
Sign up to join our community!
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
✳️Cinnabar is a toxic mercury sulfide mineral with a chemical composition of HgS. 🔷It is the only important ore of mercury. It has a bright red color that has caused people to use it as a pigment, and carve it into jewelry and ornaments for thousands of years in many parts of the world. Its […]
🔷Kimberlites, named after the town of Kimberly, South Africa, where they were first described, are volcanic rocks that originate in Earth’s mantle.🔷They are mined exclusively for diamonds. The photo shows the “Big Hole” at Kimberly.🔷The Hole was mined from 1871 to 1914 and reached a depth of 240 m below the surface. Subsequently it filled […]
Geological Time Scale The geological time scale is a system of chronological measurement that relates geological events and geological time to a numerical scale. It is used to describe the timing and relationships between events that have occurred throughout Earth’s history. The time scale is divided into four main parts: Eons, Eras, Periods, and Epochs. […] Table of Contents Toggle Geological Time Scale
What are Rare Earths? The Japanese call them “the seeds of technology.” The US Department of Energy calls them “technology metals.” They make possible the high tech world we live in today – everything from the miniaturization of electronics, to the enabling of green energy and medical technologies, to supporting a myriad of essential telecommunications and defense systems. […] Table of Contents Toggle What are Rare Earths?Which Elements ...
Geology 101 is the study of the Earth and its materials, structures, processes, and history. It is a broad field that encompasses many different disciplines, including mineralogy, petrology, paleontology, and geophysics. Geologists study the Earth’s physical features, including its rocks, minerals, soils, and water. They also study the Earth’s internal structure and the processes that […] Table of Contents Toggle Why Study Geology?What Do GEOSCIENTISTS ...
What is Volcano I heard about the volcano before 🤔??….We all see volcanoes in movies and news, but did you ask yourself why or how do they happen? On our trip today, we will explore the volcano and see its formation, why it happens, and how.. Are you ready, hero ??Let’s start our journey The […] Table of Contents Toggle What is VolcanoOne ...
An unconformity is a surface of erosion or non-deposition that separates two rock units that have different ages. It represents a time gap in the geologic record, and it occurs when sedimentary rocks are tilted, uplifted, and eroded before new sediment is deposited on top of them. There are three types of unconformities: Disconformities A […] Table of Contents Toggle There are three types of unconformities:
Minerals are homogeneous, naturally occurring, inorganic solids that have a definite crystalline structure and chemical composition. In 1995, the World Minerals Organization put another definition saying that “a mineral is an element or a chemical compound that is naturally crystalline and formed as a result of geological processes.”Minerals have their own specific physical properties which […] Table of Contents Toggle Minerals are classified according to their chemical composition.
The difference between mineral, metal and ores Many people confuse three completely different classes of substances (minerals, ores, and metals), so that metal becomes a mineral, and all minerals become ores. Minerals Minerals are inorganic solids (elements or compounds) that have distinct physical properties. Each substance has a known atomic structure and a fixed chemical […] Table of Contents Toggle MineralsOres materialsMetals
Geology online Quizzes questions and answers. Free online quiz with multiple-choice questions (MCQ) without registration. Geology Multiple Choice Questions geology questions and answers | geology questions for competitive exams | geology exam questions. Geology quiz questions and answers.geology quizes. Geology online quiz.
Dredging is the underwater excavation of a placer deposit by floating equipment. Dredging systems are classified as mechanical or hydraulic, depending on the method of material transport. The bucket-ladder, or bucket-line, dredge has been the traditional placer-mining tool, and it is still the mostRead more
Dredging is the underwater excavation of a placer deposit by floating equipment.
Dredging systems are classified as mechanical or hydraulic, depending on the method of material transport.
The bucket-ladder, or bucket-line, dredge has been the traditional placer-mining tool, and it is still the most flexible method for dredging under varying conditions. It consists of a single hull supporting an excavating and lifting mechanism, beneficiation circuits, and waste-disposal systems.
The excavation equipment consists of an endless chain of open buckets that travel around a truss or ladder. The lower end of the ladder rests on the mine face—that is, the bottom of the pond where excavation takes place—and the top end is located near the centre of the dredge, at the feed hopper of the treatment plant.
The chain of buckets passes around the upper end of the ladder at a drive sprocket (called the upper tumbler) and loops downward to an idler sprocket (the lower tumbler) at the bottom. The filled buckets, supported by rollers, are pulled up the ladder and dump their load into the hopper.
After the valuable material has been removed by the treatment plant, waste is dumped off the back end of the dredge.
The clamshell dredge, another mechanical system, is characterized by a large single bucket operating at the end of cables.Although it can operate in deeper water than other systems and handles large particles and trash well, it has the disadvantage of being a discontinuous, batch-type system, taking approximately one bite per minute.
In pure hydraulic dredging systems, the digging and lifting force is either pure suction, suction with hydrojet assistance, or entirely hydrojet.
They are best suited to digging relatively small-sized loose material such as sand and gravel, marine shell deposits, mill tailings, and unconsolidated overburden.
Hydraulic dredging has also been applied to the mining of deposits containing diamonds, tin, tungsten, niobium-tantalum, titanium, monazite, and rare earths.
The digging power of hydraulic systems has been greatly increased by the addition of underwater cutting heads.
The cutter suction dredge has a rotary cutting head or other excavating tool for loosening and mixing soil at the face of the mine.
The material falls downward to the mouth of a centrifugal pump, and this transports the slurry (containing 20 to 25 percent solids) to the processing plant. Normally, the dredge is held in place during cutting by a pile called a spud. Winches and wire ropes are used to swing the dredge in an arc around the spud until all the material in the arc has been removed.
The dredge is then moved ahead and the process repeated. The cutter suction dredge is most suitable for mining softer deposits where the material is of a relatively low specific gravity or fine particle size—for example, in sand and gravel pits, phosphate mines, and various salt deposits.
See less