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Field report · Oct 16, 2026 · 5 min read

The Antminer S19j Pro paused once in 2024, moved to Nigeria once, and has paid for its box

The S19j Pro was bought in August 2023 and has run through the 2024 halving and the trough that followed. It was switched off once, for seven weeks, then crossed to Nigeria, where its power line sits below hashprice.

Firsthand card: "Antminer S19j Pro field report", the machine's store photo beside its name

Bitmain Antminer S19j Pro (100 TH/s)

Three years, one pause and one move

The S19j Pro is a 100 TH/s air-cooled Bitmain machine rated at 29.5 J/TH and 2,950 W, announced in June 2021. Bought once its price settled, on 14 August 2023, it cost $1,239. Landed at our Argentina site, with freight, duty, setup and its place in a rack, the all-in cost was $2,311.

In 1,112 days since it has mined and kept 0.0893 BTC, worth about $7,286 today, for $3,428 of electricity. That is $3,858 of cashflow, or 1.7× its landed cost, and an average of about $38,400 of power per coin over the whole run. Not one coin was sold.

Chart: Coins kept since August 2023, the electricity that made them, the pause, the move to Nigeria and where it lands by the 2028 halving.

56% of its coins came before the halving

From the day we bought it to the April 2024 halving the machine ran 250 days and put 0.0503 BTC in the wallet, clearing about $3.85 a day after electricity. On 20 April 2024 the block subsidy halved, and every machine on the network began producing half as many coins for the same electricity.

The 862 days since have produced 0.0391 BTC at about $1.02 a day after power. Same machine, smaller day. Hashprice was $71.63 on the day it was bought and $38.89 on 15 October 2026, on our hashprice chart.

Chart: Profit over electricity, month by month: 6¢ in Argentina, then 3.9¢ in Nigeria after the move. The step down in April 2024 is the halving.

August 2024: seven weeks dark

A machine's line is the hashprice at which it stops covering its own power. At 29.5 J/TH a petahash uses 708 kWh a day, which is $42.48 at Argentina's 6¢ and $27.61 at Nigeria's 3.9¢. Hashprice fell to $37.70 on 5 August 2024, the lowest day of the year after the halving, and the machine was switched off on 26 August 2024.

It stayed off for 48 days and was switched back on on 14 October 2024, when hashprice was $46.80. No coins were mined in between and none were lost. The S19j Pro+, at 27.5 J/TH, has a line of $39.60 at 6¢ and ran straight through the same weeks. Two J/TH is the whole difference between a pause and none.

Its line was $42.48 a petahash a day at 6¢. Hashprice touched $37.70.

Chart: Network hashprice per petahash per day. The S19j Pro's 6¢ line, $42.48, sat above the August to September 2024 trough. Open the chart

One move, to Nigeria, on 8 January 2025

After the restart it ran in Argentina for 86 more days and then made its one move, to Nigeria, where it has run 647 days at 3.9¢. It spent 379 days in Argentina before the pause. A crossing is freight, customs and downtime at both ends, so a machine makes it once and does not shuttle, which is the rule in a machine crosses to cheap power once.

At Nigeria's 3.9¢ its line fell to $27.61. Hashprice's lowest day since the move was $27.74, on 6 June 2026, and its lowest 30-day average $30.09, to 3 July 2026. Both are above the line, and the machine has not been switched off since.

Chart: What a coin cost in electricity each month against what a coin was worth. The gap is the margin, and it narrows after April 2024.

Where it stands now

Hashprice was $38.89 on 15 October. That is above the Nigerian line of $27.61 and below the Argentine line of $42.48, which is why today's cost per coin is $61,000 at 3.9¢ and $93,900 at 6¢, and why one bought at today's price returns 15% in a year in Nigeria and less than its power costs in Argentina.

The forward figures to the April 2028 halving add 0.019 BTC, $2,411 with bitcoin back at $124,493. That is today's conditions held flat, not a forecast, and it makes the S19j Pro a machine that does its remaining work in Nigeria.

What it says about the next machine you buy

Nothing about this machine failed. It mined every day it was on, it kept every coin, and it covered its landed cost 1.7×. The one stop came from its efficiency: a couple of J/TH separate the machine that pauses from the machine that does not, and that margin is set at purchase. The guide to efficiency and halvings is the long version.

The same logic runs forward. A machine at 15 J/TH has a line of $21.60 at 6¢, and one at 9 J/TH, $12.96. The figure below ranks what we would put in its place today, on cost per coin and then year-one return.

What we would put in its place today, ranked on cost per coin and then year-one return.

Which machines this covers

Disclosure

Firsthand Bitcoin sells and hosts mining hardware, including this machine. No manufacturer, distributor or affiliate programme paid for or reviewed this page and we take no commission on the links above. Historical figures are computed from daily bitcoin price and network hashprice, each day valued at its own prices. Nothing here is investment advice.