Appendix 2-2

- 98 -

Archaeological excavation report (Survey of underground remains boundaries at the

Hashima Coal Mine remains)

For the purpose of examining the production facilities and the seawalls, an excavation study was conducted at

the remains of the Pit No. 1 winding machine room in 2014, and a survey to find out whether or not any remains

of seawalls were preserved at the schoolyards of the former Takashima Town Hashima Municipal Elementary and

Junior High Schools in 2014 and 2015.

An outline of the studies is provided in the following:

Trench No. 1 Pit No. 1 winding machine room (2014)

Trench No. 2 (2014)

Trench No. 3 (2014)

Trench No. 5 (2015)

Trench No. 4 (2015)

Appendix 2-2

- 99 -

Figure 2-3-80. Diagram of locations for excavation study

1) Pit No. 1 winding machine room excavation

a) Outline of survey

Pit No. 1 was a pit shaft that was opened in the early days of the Hashima Coal Mine. Mining was started in

1886, and the mine was closed in 1898. Based on a study of a topographic map of the present day overlaid on an

old map, it was estimated that the mine entry was beneath Building No. 65, and it would therefore be not possible

to conduct an investigation there. At a location estimated to have been the Pit No. 1 winding machine room,

however, several exposed patches of brickwork were observed. An excavation study was therefore conducted to

determine whether or not there were any remains of the structure there.

■エリア区分

■道路

生産施設エリア

居住施設エリア

凡　　　例

護岸エリア

■建物 ・施設の現状

残存建物 ・施設

一部残存建物 ・施設

崩壊建物 ・施設

見学用通路 （現在）

主要な通路 （閉山前）

人道トンネル （閉山前）

天川護岸露出部

下部天川護岸露出部

天川護岸崩壊部

■護岸遺構の現状

Legend

Offi

ce e

ntrance

Pit

No.3

1F E

lect

ric

equip

ment s

hop

2F O

ffice

1F S

afe

ty

lam

p room

ele

vatin

g

mach

ine

Areas

Production facilities

Residential facilities

Seawall revetment

Current status of buildings / facilities

Visitor walkway (current)

Buildings, facilities remaining

Min

e e

ntry

landin

g

(phys

ical insp

ect

ion

scre

enin

g)

Offi

ce

1F M

ine e

ntra

nce

Pool

Genera

l offi

ce

13-to

n c

rane m

ount

Mate

rial s

tora

ge

ware

house

(Form

er pit

No.

3 w

indin

g m

ach

ine room

)

bath

tub

bath

room

for m

iners

bath

room

for e

mplo

yee

Buildings, facilities partially remaining

Buildings, facilities collapsed Pit

No. 2

win

din

g

mach

ine room

1F L

ock

er ro

om

Current status of seawall revetments

Pie

r

Engin

eerin

g

sect

ion p

lant

(sm

ithy) P

late

w

ork

ing

shop

Oil

ware

house

Tunnel

Pie

r

Unders

ea w

ate

r pip

e in

let

In-p

lant

ware

house

Engin

eerin

g

sect

ion p

lant

(fin

ishin

g p

lant)

Subco

ntract

or

housi

ng Genera

l offi

ce

(Min

e m

anager’s

offi

ce, g

enera

l affa

irs,

and o

thers

)

Lum

ber y

ard

Coal-m

inin

g

mach

ine p

lant

Site of excavation

Fifty steps

Pit No. 1 mine entry

Tennis

court

Child

ren's

park

Ele

ctric

mate

rial

ware

house

Eye

gla

ss

20-to

n c

rane m

ount

Flo

tatio

n

mach

ine

room

Coal a

naly

sis

room

H

eavy

oil ta

nk

Coal s

tora

ge y

ard

belt

conve

yor

Old

dock

Gre

enh

ouse

Com

pre

ssor r

oom

Mate

rial s

tora

ge w

are

house

An old map, from 1917

Dock

Child

ren's

park

Pit

No. 1

Win

din

g

mach

ine room

(e

stim

ate

)

Principal road (before mine closure)

Pit

No. 1

(est

imate

)

Fre

sh a

ir fa

n

room

P

it N

o.4

win

d tu

nnel

Fan (re

serv

e)

Foundatio

n o

f the

derric

k（pit

No.4）

Coal w

eig

hin

g

room

Roads

Pit

No. 2

C

apst

an

Loadin

g o

ffice

Adit

rem

ain

s

Loadin

g b

elt

conve

yor

Lig

hth

ous

e

ISeaw

ate

r pum

p

Pit

No. 2

Coal r

efu

se c

onve

yor

belt

entrance

Oliv

er f

ilter r

oom

RA

W c

oal p

ock

et

Wate

r tank

Pit

No. 2

win

din

g

mach

ine room

fo

undatio

n

Baum

-type J

ig

Tip

ple

Pit

Tunnel for human use (before mine closure)

Amakawa masonry revetment exposed Amakawa masonry revetment lower parts exposed

RA

W c

oal p

ock

et

Chidori-so (housing)

Amakawa masonry collapsed

Hash

ima G

inza

Iron p

ole

pla

nt

Pool e

ntra

nce

15-to

n c

rane m

ount

Shio

furi

mach

i

Berth

ing d

olp

hin

Loadin

g p

ier

Hell steps Subst

atio

n

Fre

shw

ate

r

tank

Com

pre

ssor r

oom

Com

pre

ssor

room

Sm

oke

stack

Gre

enhouse

Main

fan room

Fan (m

ain

)

Market

Pit

No. 4

w

indin

g

mach

ine

room

P

it N

O. 4

Tunnel c

onve

yor r

Tunnel c

onve

yor

Min

e c

ar re

pair

shop

Dorr th

icke

ner

Blo

wer ro

om

Loadin

g p

ier

Loadin

g p

ier

Appendix 2-2

- 100 -

b) Findings

At Trench No. 1, remains of a structure were found in which bricks were laid to form a pair of hyperbolas, with

the area between the two curves also made of bricks, although partially ruined. Each of the arcs formed a part of a

cylinder, which was mortared. Inside the larger arc, another, smaller cylinder, which was also laid in bricks, was

built. Structures and functions of this brick structure were not yet known. Considering that the bricks used here

were those with a thickness of approximately 4 cm, or so-called “konjac bricks,” it is likely that this structure was

related to Pit No. 1 winding machine room.

Figure 2-3-82. Trench No. 1. Ground area plan

Photo 2-3-89. Work at Trench No. 1 Photo 2-3-90. Trench No. 1, excavation work completed

Figure 2-3-81. Diagram of Pit No. 1 winding machine room study locations

Appendix 2-2

- 101 -

2) Survey on presence of remains of seawalls

a) Outline of survey

For the purpose of finding out whether or not any remains of the seawalls, which were built in 1899 and

subsequently buried underground at the Hashima Coal Mine remains, were presented, a survey was conducted

over a period of two years, in 2014 (Trenches No. 2 and No. 3) and 2015 (Trenches No. 4 and No. 5). The locations

of the trenches are as shown in Figures 2-3-83 and -84. The survey was conducted manually to determine whether

or not remains were presented, and their shapes, if any.

The locations of the trenches to study were determined based on Takashima Coal Mine Survey Report, published

in March 2014 (City of Nagasaki, 2014).

Site of excavation

Seawall believed to have been built in 1907 reclamation/expansion

Figure 2-3-83. Diagram of locations for survey on presence of seawall revetments remains

Legend

Areas of land reclamation over the years

Area in 1893

Reclaimed in circa 1897

Reclaimed in circa 1899

Reclaimed in circa 1900

Reclaimed in circa 1901

Reclaimed in circa 1907

Reclaimed in circa 1931

* Sites of land reclamation and pit shafts were estimated based on An Overview of Hashima Island, published by Mitsubishi Mining Co., Ltd. Takashima Island Office, August 1953.

Appendix 2-2

- 102 -

b) Findings

At Trenches No. 2 and No. 3, remains of the stone seawalls built in 1899 were found at the locations predicted.

There were foundations of buildings above the stone walls found at Trench No. 2, where it was observed that

remains of structures from the Meiji to the early Showa eras (the late 19th to early 20th century) were preserved in

good condition. As the purpose of the 20014 survey was to determine the locations of stone seawalls, the stone

walls were not dug up in their entirety. Nevertheless, three rows of stone walls were observed, in which stones

were laid in mortar using the Nunozumi technique. The upper parts were finished in Amakawa, a type of traditional

earth mixture that is light orange in color and is often used in this region. Given that the Amakawa-covered parts

extended further beyond the estimated counterfort length, it is possible that the Amakawa finish may not have been

used only in the stone walls but extended to the ground surface of that time (Figure 2-3-88 and Photo 2-3-111).

At Trenches No. 4 and No. 5, concrete foundations built on brickwork were observed. Given their locations,

they are considered to have been the foundations of the former primary school building, whose construction was

completed in 1934, after the 1931-32 land reclamation. Although remains of the stone seawall built in 1899, which

was the original target of the survey, could not be found definitively, it is likely that they may remain underground,

beneath the foundation of the former primary school building. As was the case with the remains exposed above

ground, the shaft line of the foundations ran along the topographical features, namely diagonal to the Japanese

national coordinate.

Larger view

Figure 2-3-84 Locations of trenches (Composite of maps showing areas of land reclamation over the years)

Area reclaimed in circa 1931

Area reclaimed in circa 1899

2年頃の拡張地 Trench No. 4

Trench No. 2

Trench No. 3 Trench No. 5

Appendix 2-2

- 103 -

Trench No. 2

Trench No. 3

Trench No. 4

Trench No. 5

Figure 2-3-85. Ground area plans of trenches

Appendix 2-2

- 104 -

Figure 2-3-86. Elevation plan of former seawall revetment (Trench No. 2)

c) Unearthed items

A total of 51 items were unearthed from Trench No. 4, including bricks, roof tiles, hardware, and porcelains.

One unearthed items of note was engraved pieces of a roof tile that appear to bear the letters "上 吉武.” The

engraving is believed to indicate the name of the manufacturer that created the roof tiles.

Photo 2-3-91. Unearthed items Photo 2-3-92 Unearthed items (engraved rood tile)

Mortar coming off

Am

akaw

a

Mortar

Mortar

Mortar

Mortar

Mortar

Lowest level exposed in

excavation

Mortar coming off

Appendix 2-2

- 105 -

Photo 2-3-93. Trench No. 1, excavation work completed Photo 2-3-94. Trench No. 2, stone seawall

Photo 2-3-95. Trench No. 3, excavation work completed Photo 2-3-96. Trench No. 3, remains of foundation

Photo 2-3-97 Trench No. 4, excavation work completed Photo 2-3-98. Trench No. 4, remains of foundation

Photo 2-3-99. Trench No. 5, excavation work completed Photo 2-3-100. Trench No. 5, soil layers

Appendix 2-2

- 106 -