I believe the two messages that you've got from our electric company actually answer your question regarding "Can they see this". Just to give you an idea on what do 12.000 kW/h consumption represent:
According to a survey from Ovo Energy
[1], an energy supply company based in Bristol, the average 24-hour electricity consumption from a sample of 250 British homes (2012) looks like this:
As you can see from the graph, the consumption goes up accordingly to certain hours in the day: During sleeping hours the consumption is at it's lowest (understandably) and it hits it's peak around evening/dinner time ( 700 watts). As you can see per the graph if we were to choose a specific time period and sum all the energy consumption, we wouldn't get anywhere near 12.000 kW/h (take in mind, we're talking about 250 homes).
If we go back a bit in that article we get a comparison of the average electricity use per household if different areas around the globe:
Understandably your energy consumption will be higher depending on the region of the glove you are in but what concerns UK (since this is a UK based study) we're talking about an average of 3700 kWh/year. Even if we use the data from a detached house we get around 4153 kWh/year (no heating). Since this is an example we'll consider the extreme case : 6000 kWh/year .
In your post you state that you have 10 Antminer S9S. The
specifications on Bitmain website state that we're talking about 1323 watts but they also say that it may have around 10 % discrepancy, so we'll assume 1400 watts for the example (I'll assume that you mine 24/7 in a 30 day period):
1,400 x 24 x 30 = 33,6 watt hours x 30 = 1,008 kW/h
You've got 10 of those so : 10 x 1,008 = 10,080 kW/h . I believe this ends up matching your calculation because we're not talking about the energy consumption that you need to keep the system cooled. I'm sure that the final consumption will be around your number.
So if we multiply that by 12 months : 10,080 kW/h x 12 = 120,960 kWh/year . If we use the previous example (6.000 kWh/year -> which may be an exaggeration) you consume the equivalent of 20,16 houses.
Normally the transformer that is installed in the area is designed to cover all the needs of a specific number of services / houses. If a single house represents 20 houses it means that the transformer has to input more energy to satisfy all the remaining needs for a specific area.
So, in short, yes your electric company can easily guess from where the energy consumption is coming from. I don't know specifics but whenever you build a house you have to let the main council of the area and the electric distributor know how much do you estimate in order for them to see if the main transformer has enough free capacity to deliver that need. If, in some rare instance, the whole neighborhood gets shutdown I'm sure they'll be looking why/what caused the overload in their systems.
[1] https://www.ovoenergy.com/guides/energy-guides/how-much-electricity-does-a-home-use.html
