The Lucara Diamond Corporation in Vancouver, British Columbia, has begun to get results from their latest diamond endeavor. The Mothae Diamond Project is taking place in Lesotho, Africa. The processing of three bulk samples is complete and has yielded 267 diamonds. The total weight of these diamonds is 132.31 carats. Of the 267 diamonds nine are more than 2 carats with the largest stone being over 8 carats. These are the first of the results from the sampling program that took place in March.
The Mothae Diamond Project is conducting additional sampling to include approximately 30,000 tons of earth. The sampling program will help to determine whether or not the area has enough diamonds to continue mining efforts. If this first round of testing proves to be successful another 70,000 tons of earth will be sampled. Sampling helps companies to determine whether the mine is going to provide the amount of diamonds and quality of diamonds that they are looking for. It is helpful to understand how diamonds are formed.
Diamonds were formed under the earth’s crust millions of years ago. Pockets of carbon dioxide existed deep inside the earth. Extreme heat and pressure caused the carbon dioxide to crystallize. This crystallization process took many thousands of years to complete. The diamonds were very deep in the earth but pressure that built up causing volcanic eruptions brought diamonds closer to the surface of the earth.
Diamonds come in a variety of colors. Diamonds that are perfectly white, also known as completely colorless, are made up of carbon atoms that are arranged in a perfect tetrahedral lattice. This atomic structure does not allow any light to be absorbed into the diamond, thus giving it the appearance of being completely colorless. This structure doesn’t exist because while they are formed diamonds are subjected to extreme pressure and temperatures. The temperatures are estimated to range from 2300 to 3600 ? F. At these high temperatures the structure of the diamonds is changed and the tetrahedral structure allows it to absorb other types of atoms. This is what introduces color into the diamonds.
Diamonds are classified by how much color they have. Type I diamonds have absorbed a small amount of nitrogen atoms. Nitrogen atoms absorb blue light so diamonds that have been formed with nitrogen have a yellow tint. Most diamonds, as many as 98% of all diamonds, are Type 1a diamonds with a pale yellow tint. Type 1b diamonds absorb blue and green light and have a darker appearance – often a canary yellow. This is a rare color and less than .1% of diamonds fall into this category. Type II diamonds are those that are the purest and have absorbed the least amount of carbon dioxide, making them appear colorless. Fewer than 2% of all diamonds are Type II diamonds yet they are the most sought after and most expensive of all diamonds.
Many times the location of the diamonds helps to determine the type of diamonds that are present. This is usually due to the amount of nitrogen and other minerals in the earth. The first diamonds were found in ancient India. Diamonds have been found in Brazil in the early 1700’s and in Siberia in the mid 1950’s. In the 1860’s diamonds were found in South Africa, where most diamonds come from today.
The sampling of diamonds found at the Mothae Diamond Project is encouraging. The company issued a statement saying in part “We are encouraged with the number of relatively large stones recovered to date and indications of a potentially coarse diamond size distribution at Mothae. We are looking forward to further results and a detailed evaluation of the diamonds after completion of the initial sample”
Samples are processed using a system called “dense media separation” or DMS. The plant that processes the samples can operate at about 20 tons per hour. The process can recover diamonds of varying sizes from 2 mm to 18 mm. Most of the process uses a continuous grease belt except for a very course fraction that must be hand sorted. The company hopes to have the initial sampling completed by the end of June.
The Mothae Diamond Project is located in close proximity to another mine that has extremely good success. Letseng is one of the world’s most important producers of large diamond gemstones. The company is hopeful that their project will be just as successful as Letseng. It is probable that similar diamonds are located nearby making the project a very hopeful one for all concerned. If the project continues to produce diamonds as those found in the initial sampling the Mothae Diamond Project could become one of the most successful diamond mining projects in the world. The sampling is being overseen by Mineral Services of Canada, a qualified company in diamond sampling.
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