Chapter 82: Gravity Anomaly
The students' faces were all darkened from days under the sun, but their eyes remained bright as they curiously looked at Li Tang.
He didn't look much older than them.
"Hello, everyone. My name is Li Tang," Li Tang said with a friendly smile.
"Hello, Senior!" several students greeted. Many of them, lacking social experience, were still shy, but a few more outgoing ones began to speak up.
"Senior, is Wu Mining Group hiring this year?"
"Can you help us all get in? We heard from Senior He that working with you means earning over a thousand yuan a month!"
"Are you a top executive at Wu Mining Group?"
"Why do people from the Geological Survey Institute always talk bad about you?"
Li Tang seemed approachable, and with someone breaking the ice, the atmosphere quickly warmed up. Even the shy students started to gather around and ask questions. Among them were two girls with sun-tanned wheat-colored cheeks, standing at the back, curiously peeking forward.
"Wu Mining Group recruits every year. There are always openings," Li Tang answered warmly. "I'm not a high-level executive. I'm just about your age. I started working only last year, and I have no control over hiring decisions."
He chatted casually with everyone.
Before long, a cook hired from the local area brought out dinner. Everyone had been running around all day and was famished, so they left Li Tang's side and swarmed the table with their bowls.
After a long, exhausting day, everyone had a huge appetite, each person loading up with a full bowl of rice.
The food was generous—meat, vegetables, well-prepared, and delicious.
After eating, Zhang Zhongyu showered and came out to find Li Tang sitting by the door. He grabbed a stool and joined him.
"Teacher Zhang, thank you for your hard work," Li Tang said as he turned toward him.
"We're being paid. Everyone's motivated." Zhang Zhongyu smiled. "Did you manage to take care of the urgent matter in Yanjing?"
"It wasn't a big deal."
Li Tang pointed at the three gravity meters placed inside the house. "I remember when I was still in school, we only had one high-precision gravity meter. Did the school buy two more?"
"They're borrowed. I mentioned in class that we had a survey project, and quite a few students were eager to join. So I borrowed more instruments so everyone could get some field experience. It'll help them in their future careers."
"Did you sign a contract with Huazhou Aluminum Plant? Did they try to lowball you?" Li Tang asked with concern.
"We did sign a contract, and it followed the standard budget." Zhang Zhongyu added with excitement, "Director Luo agreed to our survey plan and budget on the spot as soon as he heard you recommended us."
"That's good to hear."
Gravity surveys were quick. At each survey point, you just had to place the instrument on the ground for a few minutes and record the data.
Due to the large survey area and high data point density, it still took more than half a month to complete all measurements.
As for data analysis and report writing, Zhang Zhongyu stayed up late several nights in a row to finish everything as quickly as possible.
At the same time, the geophysical team from the Geological Survey Institute carried out controlled-source audio-frequency magnetotelluric (CSAMT) surveys, almost completing the work in parallel.
Luo Qinzhong brought in the aluminum ore expert Bi Junjie from another mine to help review the results from the Yunyue Bauxite Project.
With conditions being simple, the group gathered in a local farmer's courtyard.
"From the field mapping we've done so far, it's clear that the earlier records were accurate. We haven't found any signs of bauxite in the project area," Ding Shaoying summarized the recent geological work.
Up to now, traditional geological prospecting had confirmed their earlier assessments.
No signs of bauxite had been found in the area Li Tang selected.
According to conventional bauxite prospecting theories, large-scale bauxite formations must have undergone weathering and leaching at the surface.
They must be within 150 meters of the surface.
No one in the field would look for bauxite deeper than that.
Any professional geologist who did so would be deemed out of their mind.
Or, they would be a complete amateur.
Ding Shaoying had always stood firmly by this view. That's why he rarely showed Li Tang any respect. "Based on current surface work, I don't think it's necessary to continue this project."
He turned to Luo Qinzhong. "From the standpoint of Huazhou Aluminum Plant's interests, continuing this work would just waste money. Even we feel uneasy spending the exploration funds."
"I understand." Luo Qinzhong gave a bitter smile.
He had been listening to Ding Shaoying complain quite a bit lately.
They had worked together for years, and he knew Ding really meant what he said.
Still, the geophysical surveys had been completed. They at least needed to analyze the results.
He tilted his head toward Li Tang and smiled. "Li Tang, you've seen the geophysical data. Why don't you give us your interpretation?"
Li Tang turned to Zhang Zhongyu. "Teacher Zhang, please go over the gravity survey results first."
"Sure." Zhang Zhongyu didn't hesitate. He laid a large piece of millimeter graph paper on the ground and began explaining without notes. "This is an isometric contour map from the gravity survey. You can clearly see several gravity anomaly zones within the project area. Especially in the central region—there's a large area with high gravity values. We infer that there's a dense rock mass beneath these anomalies, forming a strong contrast with the surrounding rocks. The anomaly values are quite high, suggesting a significant mass."
"Can you tell what kind of high-density body it is?" Li Tang asked.
Zhang Zhongyu gave a helpless smile. "I cross-referenced the surface geology, but I couldn't find any matching strata. It's difficult to determine what's causing the anomaly underground. The surrounding area mainly consists of limestone and dolomite."
"So on the surface, there's no indication of what's beneath the gravity anomaly?"
"Based on the surface bedrock, nothing visible could cause such a strong gravity response."
"Could it be a lens-shaped ore body—like pyrite—with higher density than the surrounding rock? Or could the anomaly be caused by bauxite?"
"It's possible. But without a physical model for bauxite, it's hard to do a proper inversion analysis and conclude whether it's bauxite or something else," Zhang Zhongyu said, spreading his hands.
Geophysical methods had their advantages—fast, deep-reaching.
But they also had a major downside: interpretation was highly ambiguous. It was nearly impossible to definitively identify rock types just from survey data. In the end, drilling was needed to verify.
"Got it," Li Tang nodded.
In truth, he had already basically pinpointed the location of the bauxite deposit.
Because he was the only one who knew—there had to be a massive bauxite deposit under this land.
The only unknown was its exact coordinates.
Now, with the microgravity anomalies identified, he had found the spot.
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