Cost of revenue. For the six months ended June 30, 2023, cost of revenue was mainly comprised of cost of revenue after inter-segment elimination from the mining pool business of US$125.3 million, the cryptocurrency mining business of US$2.3 million and the data center business of US$11.5 million. For the six months ended June 30, 2022, cost of revenue was mainly comprised of cost of revenue after inter-segment elimination from the mining pool business of US$448.0 million, the cryptocurrency mining business of US$13.7 million, and the data center business of US$4.3 million. The cost of revenues from mining pool business for the six month ended June 30, 2023 included US$5.3 million from primary mining pool services and US$120.0 million from sub mining pool services, while the cost of revenues from mining pool business for the six months ended June 30, 2022 were all from primary mining pool services.
The gross profit for the six months ended June 30, 2023 and 2022 were US$0.5 million and US$2.8 million for the mining pool business, and US$9.3 million and US$24.1 million for the cryptocurrency mining business. The gross losses for the six months ended June 30, 2023 and 2022 were US$2.0 million and US$0.9 million for the data center business. The gross profit from mining pool business for the six months ended June 30, 2023 included gross profit of US$0.1 million from primary mining pool services and gross profit US$0.5 million from sub mining pool services, while the gross profits from mining pool business for the six months ended June 30, 2022 were all from primary mining pool services.
With respect to the mining pool business, the gross profits are mainly due to the continuous declines in cryptocurrency prices, which has drove down the whole computing power since the first half of 2022 and remained lower prices in the first half of 2023 as compared to the corresponding period of 2022. And for safety elements, the Company has also ceased registering new users from Russia and started to retire accounts of existing users from Russia since March 2022, which could also be a negative impact on mining pool business.
With regards to the cryptocurrency mining business, the gross profits are largely driven by the cryptocurrency prices. The decreased gross profit was primarily attributable to lower cryptocurrency asset prices in first half of 2023 as compared with the overall prices in the first half of 2022, which led to our suspension of the operation of certain types of BTC mining machines. And after the Ethereum Merge (The Ethereum Merge, namely, of the Ethereum Mainnet and the Beacon Chain Proof-of-Stake system, occurred on September 15, 2022.), the Company changed its strategy to ETC cryptocurrency mining operations, which also led to an obvious declines of gross profits.
For the data center business, revenues are generated from providing its customers with rack space, utility, and cloud services such as virtual services, virtual storage, and data backup services. Cost of revenue is primarily comprised of direct production cost related to data center service as well as depreciation and amortization of the data centers. The increased gross losses of data center business for the six months ended June 30, 2023 were mainly attributable to the continuous declines in cryptocurrency prices since the second quarter of 2022, which led its customers to suspend their cryptocurrency mining operations.
Sales and marketing expenses. Sales and marketing expenses decreased of US$0.1 million from US$0.3 million for the six months ended June 30, 2022 to US$0.2 million for the six months ended June 30, 2023.
General and administrative expenses. General and administrative expenses decreased from US$12.4 million for the six months ended June 30, 2022 to US$11.1 million for the six months ended June 30, 2023. The decrease was mainly due to (i) a decrease of US$2.5 million in share-based compensation expenses associated with share options granted to our directors and employees mainly expensed in 2022, (ii) a decrease of US$1.1 million in third-party professional service fees, which was less acquisition activities occurred in 2023, and (iii) a decrease of US$0.7 million in depreciation and amortization expense, which was partially offset by (iv) an increase of US$3.0 million in consulting expenses related to the production of the Company’s LD4 DOGE/LTC mining machine.
Service development expenses. Service development expenses decreased from US$2.2 million for the six months ended June 30, 2022 to US$0.1 million for the six months ended June 30, 2023. The decrease was primarily due to a decrease of US$1.3 million in salary and benefit expenses for employees primarily due to a decrease in staff costs and benefits as a result of a decrease in headcount.
Other operating income
Other operating income remain unchanged of US$0.2 million for the six months ended June 30, 2022 and 2023.
Net (loss) gain on disposal of cryptocurrency assets
Net loss on disposal of cryptocurrencies decreased from US$2.1 million for the six months ended June 30, 2022 to net gain of US$5.8 million for the six months ended June 30, 2023, which was related to decreasing market prices for cryptocurrencies by using first-in-first-out (“FIFO”) to calculate the cost of disposition.