Alrosa kicks off diamond exploration in Zimbabwe
Russia’s Alrosa (MCX:ALRS), the world’s top diamond producer by output, has begun prospecting and preliminary exploration works for deposits in Zimbabwe, as part of a partnership with the country’s Consolidated Diamond Company (ZCDC).
The move is a welcome boost to the southern African nation’s attempts to expand diamond mining revenues. Zimbabwe first began allowing foreign companies to dig up precious stones in 2018, opening the door to private investors.
Mines minister Winston Chitando said at the time that his office was considering letting foreigners hold majority stakes in local operations on the condition that part of their output is reserved for domestic downstream industries.
“Following the signing of a joint venture agreement with Zimbabwe Consolidated Diamond Company to develop diamond deposits, we are progressing well towards the initiation of the full-scale prospecting works this year,” Alrosa’s deputy chief executive, Vladimir Marchenko, said in the statement.
Most of Zimbabwe’s diamond fields are in Marange, in the eastern part of the country, where production is dominated by ZCDC.
In 2008, hundreds of artisanal miners were killed and thousands had to leave their homes as the military, under the former government of dictator Robert Mugabe, forced them to leave Marange.
International advocacy groups accused Mugabe of looting about $2 billion from the diamond-rich fields. The European Union lifted sanctions that curbed diamond exports from Zimbabwe at the end of 2013.
In early 2016, however, Mugabe evicted all diamond miners after they declined to merge with ZCDC.
Sector boost
President Emmerson Mnangagwa, who took office in 2018, has moved to end the country’s international isolation and attract foreign investment to boost an economy in tatters.
Campaign group and accountability watchdog Global Witness has said that Mnangagwa’s handling of the nation’s diamond industry would be the ultimate test for his commitment to economic reform and anti-corruption.
According to the organization, good governance of the country’s diamond sector is a barometer of the direction that Zimbabwe is taking more broadly in the post-Mugabe era.
“It will attest to the credence of President Mnangagwa’s claims of a zero tolerance approach to corruption and transformed economic governance,” Sophia Pickles, Campaign Leader at Global Witness, said.
Alrosa has committed to invest $12 million in Zimbabwe from 2020 to 2022. Most of the diamond fields are in Marange in eastern Zimbabwe, where production is dominated by ZCDC.
What is Cr-Mo alloy steel mill liners?
Cr-Mo alloy steel is short for chromium-molybdenum steel. In Australian and New Zealand Standard, it is the AS2074 steel standard; In the USA, it is the BS3100 steel standard. Because Cr-Mo steel has good wear resistance, toughness, and hardness, this steel widely used in casting mill liners for autogenous mills, semi-autogenous mills, ball mills, rod mills, and Vertimills.
- Low Carbon Chrome Moly Steel (300 to 370BHN): Was generally used for mill liners (AG mill, SAG mill, and Ball mill) prior to the movement to higher carbon content steels. It has excellent wear characteristics with some impact resistance, generally now used for discharge grates where slightly better impact resistance is required compared to the higher carbon chrome-moly steels or for thinner section liners.
- High Carbon Chrome Moly Steel (325 to 380BHN): This steel is now considered the main material used for SAG mill liners. There are a number of variations with either different carbon or chrome contents. The variations tend to have a bearing on the size of the liner and its section thickness. There is ongoing development within this area as the size of the liners are outstripping the properties provided by the standard high chrome-moly steels.
Cr-Mo alloy steel Mill Liners chemical composition and Specification
In Australian and New Zealand Standard, it is AS2074 L2A, AS2074 L2B, and AS2074 L2C. In the USA, it is BS3100 BW2, BW3, BS3100 BW4.
Material Composition
| Name | Chemical Elements（%） | |||||||
| C | Si | Mn | Cr | Mo | Cu | P | S | |
| AS2074 L2B | 0.4-0.8 | ≤1.2 | 0.6-1.5 | 4-6 | 0.3-1 | 0.3-0.8 | ≤0.04 | ≤0.06 |
| AS2074 L2C | 0.3-0.6 | ≤1.2 | 0.5-1.2 | 1.2-2.5 | 0.3-1 | 0.3-0.8 | ≤0.04 | ≤0.06 |
Physical Property & Microstructure
| Name | Surface（HRC） | Ak（J/cm2） | Microstructure |
| AS2074 L2B | ≥48 | ≥20 | M+C |
| AS2074 L2C | ≥40 | ≥30 | M+C |
Specification
| Size | Hole Dia.（mm） | Liner Length（mm） | ||
| ≤40 | ≥40 | ≤250 | ≥250 | |
| Tolerance | +2 0 | +3 0 | +2 | +3 |
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Post time: Jul-24-2020