After returning to Rock Fortress, the geothermal energy team worked in shifts around the clock.
"The total pipeline length is 14.62 kilometers," Benjamin said after completing the latest measurements. "Because we had to detour around three unstable areas, the actual route is 120 meters longer."
Elena nodded and marked it on the master plan. "What about the diameter? Have you worked out the optimal size?"
"Based on the combined calculations for flow rate, velocity, pressure loss, and heat loss, the optimal pipe diameter is fifteen centimeters," Aleksei said, handing over his calculations.
"Anything smaller would make the flow too fast and increase the load on the pumping stations. Anything larger would use more material and result in greater heat loss."
"What about the insulation?"
"The average winter temperature around the Great Smoky Mountains is about minus five degrees Celsius, so under normal conditions we wouldn't need much insulation.
"But last year's extreme weather brought temperatures close to minus forty.
"If we design for extreme cold, we'll need a thirty-five-centimeter layer of rock wool insulation with a waterproof outer casing."
Anna flipped through a thermodynamics manual as she spoke. "That should keep heat loss within an acceptable range."
She already had the figures prepared.
"So, once we account for joints, spare sections, and construction losses, we'll need about eighty-five metric tons of steel in total.
"The rolling mill at the Industrial Park can produce twelve metric tons of seamless steel pipe per month. We currently have eighteen tons in storage, which leaves a shortfall of fifty-five tons.
"My God. That means another seven months of production!"
"That's too long." Elena frowned. "Calista wants this finished before winter. Do we have another option?"
The meeting room fell quiet for a moment.
"Does she really think we can finish it before winter?" Benjamin asked doubtfully.
He had only joined the base with the UTK team three months ago and still had not fully adjusted to the pace at which things got done here.
Elena turned and pushed her glasses up.
"Benjamin, on my first day here, all I saw was Rock Fortress.
"There weren't even a hundred people here.
"At the very beginning, it was just Calista and her group of mercenaries.
"A few months later, we had hydropower, solar power, and walls capable of holding back walkers.
"Now look at the scale of Blackberry Ranch and the Industrial Park. What do you think?"
Benjamin opened his mouth but said nothing.
Elena paused.
"When Calista sets a goal, it isn't a wish. It's a schedule."
"All right," Benjamin finally said. "Then we can build it in phases.
"We'll use our existing stock and materials to complete Phase One first, the four-kilometer section from the hot springs to the first booster station.
"That will at least give us a proof of concept and let us verify the system's reliability while production continues on the remaining pipe."
Elena tapped a finger against the table. "But phased construction will increase the total labor required. We'll have to deploy the equipment and personnel more than once."
"Not necessarily!" Anna's eyes lit up. "The data from Phase One could help us optimize the later stages. We can treat the first section as a trial line."
The idea immediately lifted everyone's spirits.
Elena stood and began drawing a new timeline on the whiteboard.
"Good. Three phases!
"Phase One, four kilometers. Establish a proof of concept.
"Phase Two, 5.2 kilometers. Extend the system to the outskirts of Rock Fortress.
"Phase Three, the final 5.42 kilometers. Complete the entire network.
"That way, each phase will function as a complete, operational subsystem."
Benjamin nodded. "Then I'll draft a detailed plan tonight."
"Anna, you're responsible for designing the heat exchanger. Check the older literature on geothermal heating. The library should have something useful."
Elena continued assigning tasks.
"Kevin, I need you to evaluate geological stability and make sure the pipeline won't be damaged by landslides."
The meeting lasted four hours. By the time Elena finally called it to an end, it was completely dark outside.
A few days later, the geothermal energy team submitted its assessment report.
Calista went through the detailed data, hand-drawn diagrams, and the carefully planned phased construction proposal. By the time she finished, she felt confident about the project.
The geothermal heating project could now officially move forward.
...
Rickson eagerly began pulling personnel and supplies together for the geothermal heating project, temporarily leaving the other work to Leah.
With some free time on her hands, Calista found herself thinking again about the brown-haired girl with the bob cut who had been bothering her for so long.
She shook her head and decided to ask her sister.
Leah's office was a small reception room beside the command room.
Leah was bent over her desk, going through a stack of progress reports from Block D.
"Leah, have you seen a girl with a brown bob since the apocalypse? She should be around your age."
Calista recalled Martin's description and gestured with her hand near her chin.
"Her hair probably comes down to about here."
Leah had no idea where the question was coming from, but she immediately set aside the reports and frowned in thought.
"Uh, a brown bob? I'm not sure.
"To be fair, that hairstyle was pretty common before the apocalypse, but I don't think anyone at our base has it now.
"Is this important, Cali?"
"Yes," Calista admitted. "It has something to do with Silas Norton's company."
Leah's expression changed sharply, and she was just about to ask more when a voice came from the doorway.
"The photo."
Michonne had apparently been passing by on her way to the command room.
After hearing the conversation, she stopped and leaned against the doorframe with her arms crossed.
"What did you say?" Calista turned toward her.
"A girl with a brown bob," Michonne reminded her. "She was in that photo we found at Sentinel Station. The group photo with that chief researcher, Dr. De La Rosa."
Ah!
Calista suddenly remembered.
Last year at Sentinel Station, Michonne had found a photograph among a pile of research files.
At the time, Calista's attention had been entirely focused on Dr. De La Rosa because she was the chief researcher at Sentinel Station. But there had indeed been another girl beside her in the photograph.
They had been standing beneath the Eiffel Tower...
"The third person had been torn out," Michonne added, apparently reading Calista's expression. Her memory was as sharp as ever. "But the girl in the corner had a brown bob. She was standing at the edge of the picture."
"My room!" Calista suddenly blurted out, already heading for the door. "Everything we brought back from the station that never got sorted, I dumped it all in the corner of my room!"
She did not finish the thought, but Michonne already understood.
The two left Leah's office almost at the same time, leaving Leah staring after them in confusion.
Calista's room was the largest in the castle, a spacious Victorian-style suite.
One wall of the outer sitting room was lined with bookshelves packed with base records. Her desk stood neatly arranged by the window.
Michonne noticed that the opposite wall was dominated by a huge whiteboard covered with several roughly drawn circles.
Inside them were Rock Fortress, Blackberry Ranch, the Industrial Park, Knoxville, Norris Dam, Oak Ridge National Laboratory, and the prison.
Michonne's eyes brightened slightly, and she stole a glance at Calista.
Most of those places had already been secured by Calista.
That meant the remaining ones were probably places she intended to take in the future.
And when those locations were connected...
They formed one enormous circle.
The only truly messy part of the sitting room was the corner piled with several boxes and safes.
Aside from Calista Norton's files, which she had brought out of the villa when the apocalypse began, the rest consisted of nontechnical items recovered from Sentinel Station:
personal belongings, decorations, unimportant documents, and assorted objects that had never been properly categorized.
Everything related to research had been handed over to Dr. Jenner. Anything that had seemed useless at the time had simply been piled here.
"I remember it being in here!" Calista crouched and opened the top box.
Michonne remained leaning against the doorframe, making no move to help.
These were probably Calista's personal belongings, and she was not about to start rummaging through them without permission.
Unless...
"Michonne, help me look! Holy shit, this place is a disaster!"
Calista was thoroughly annoyed with herself.
She was good at plenty of things, but organization was not one of them. If she did not need something, she would shove it wherever there was space. Then, when she finally did need it, she could never find it.
A photograph that small could have ended up anywhere.
The two spent quite a while digging through the jumbled piles of papers and miscellaneous items.
In the end, it was Michonne who found it tucked inside a notebook.
The photograph with the third person torn out.