煤层的英文：
a vein of coal
coal bed
coal seam

参考例句：

top surface of coal bed
煤层顶面等高线图

Shale underlies coal.
页岩层在煤层之下。

Shale underlies the coal.
页岩层在煤层下面。

The degree of carbonization of coal depends on the temperature
煤层的炭化程度取决于温度。

The average UK coal seam is one metre thick.
英国煤层的平均厚度为1米。

The average width of the seam is more than 50 meters.
平均煤层宽度大于50米。

Because this coal bed thickness is moderate, selects the shield type hydraulic pressure support.
由于该煤层厚度适中，选用掩护式液压支架。

In order to loosen the coal, the miners made holes in the dividing wall and filled them with explosives
为了使煤层松动，矿工们在隔墙上打了炮眼，装进了炸药。

vein是什么意思：
n. 血管，静脉；纹理；叶脉；岩脉；性情
v. 使有脉络；象脉络般分布于

It is veined by railroads.
铁路线四通八达。

Radiography of veins or a vein after injection of a radiopaque substance.
静脉造影术在注入射线不能显著穿透的物质之后对静脉的放射线照相术

Varicose vein (or varix)：Twisted vein distended with blood.
静脉曲张:伴有血液潴留的静脉扭曲或扩张。

coal是什么意思：
n. 煤，木炭；煤块
v.（给…）加煤；把…烧成炭

Coal is a mineral.
煤是一种矿物。

The coal will be shipped by rail.
这些煤将用火车装运。

The boat is freighted with coal.
这条船装载煤。

bed是什么意思：
n. 床，睡眠处；睡觉；（海、河、湖等的）底部；苗床
v. 把...安置在；为…提供住宿（床位）；睡，卧

Procrustean bed
逼人就范之物

Bed rest is more like bed agony.
上床睡觉好象是种苦恼。

It has bedded into the deepest crevices of the store.
它已钻进了店里最隐避的隙缝。